Imagine a lunatic asylum with 40,000 occupants. It's located in Grant Park, right on Columbus Drive. For 18 weeks, the inmates are subjected to a restricted diet, sleep deprivation and daily corporal punishment.

Can you see it? Now imagine what would happen if, early on an autumn Sunday, the gates were thrown open and 40,000 raving madmen were told to run through Chicago's streets for as long as six hours.

Would you come watch? Of course you would, and you should -- and you can, as this, more or less, will be the scene Oct. 12 with the 26th running of the Chicago Marathon.

We are the marathoners: the few, the strong, the quite mad.

This year's Chicago Marathon promises to be one of the biggest road races ever. Despite Phidippides' fate 2,493 years ago, a record number of runners -- 36,000 more than ran the first one 26 years ago -- will be running, and $500,000 in prize money will be on the line.

Fig1. Thousands of crazy people.

It's the spectators, however, who truly make Chicago the best race in the world, and although there are plenty of guides and programs for runners, there's nothing to help take spectating to the next level. Here are a few suggestions.

Helping hands
Don't freak out if your running friends start to, well, freak out the week before the race, especially if they're running their first marathon. Fatigue and nerves will conspire to make them irritable and grouchy. They may go into Howard Hughes mode, fearful of germs and small children. After working all summer to get fit, they'll get paranoid about every last calorie. Offer a Hershey's Kiss and they'll snap. "This has an entire gram of saturated fat," they'll say. "Are you trying to ruin my marathon?"

It's normal. Give them space. See that their Brita is full and go for a walk. Just remember to remind them of their grouchiness later, during their postrace binge: Beers and ice cream will be on them.

Despite all you've heard about carbo loading, don't shower your friends with well-intentioned bagels and spaghetti feasts. Many beginners make the mistake of pigging out on carbohydrates during their taper, which could hurt them much more than the occasional Kiss. Normal meals and snacks with just a little more emphasis on carbs should suffice. Discourage seconds and large portions.

If you are going to treat your friends to a nice Italian meal out, do it on Friday, not Saturday, so that they're able to process the food in time for the race. Saturday should be all about relaxing with a small supper and watching baseball.

Special tip for runners' significant others: The night before a race, it's helpful to relieve a runner's humours, and I don't mean blowing their nose. All that effort your partner's done to improve endurance? Now is the time to return the favor with a peaceful, non-taxing workout.

Planning your attack
Be they Scrabble freaks or baseball players, I love watching elite competitors in person, and it's rare to find opportunities to get closer to the action than at a marathon; get up early and root on your favorite Kenyan. Granted, your view won't last long. Elites run about 12 mph, as fast as most people ride a bicycle or the No. 22 Clark bus, but if you're coordinated, you can change your location and catch them at several points.

Planning is important whether you're watching the two-hour-pace elites or your six-hour-pace grandmother. Study the course map the night before. Get a daylong CTA pass and watch from downtown, Belmont, Chinatown and Sox/35th. Or, for even greater mobility and to beat the crowds, hop on your bicycle and head out toward Little Italy, Greektown and Bronzeville. Just be sure to get on the interior of the course before the race blocks traffic.

Fig2. A map of the course for your convenience.

The first starting gun fires at 8 a.m. If you're looking for someone in particular, ask for their goal pace to anticipate when they'll be at various points. The elites, for example, run 5-minute miles, so they'll hit mile 12 at Orleans and Hubbard just after 9. Your friend running 10-minute miles, on the other hand, will get there after 10 (accounting for the time it takes to actually get to the starting line). You can also keep an eye out for the pace groups, leaders of which will be carrying tall signs signifying their projected time.

The sidewalks get pretty crowded, so help your runners find you by wearing distinctive clothing or waving bright signs or flags. Likewise, find out what colors they'll be wearing. Discourage white tops, because just about everyone else will be wearing white, too.

The outside of 90-degree turns are good positions to take up, because from here you get the longest view of any given runner and won't get tennis neck. And don't neglect the second-half of the race. That's where the crowds thin out, but it's also where runners begin to hit the fabled Wall. Here the tailwind of good cheer determines whether we finish or not.

Shouts and Murmurs
"Looking good," "You're almost there" and "Nice legs" are all lies, but the good kind. Keep 'em coming.

Cowbells, whistles and tambourines are all excellent noisemakers. Live music is even better motivation, but a well-chosen mix CD can do the trick. If you live along the route, put "Gonna Fly Now" from "Rocky" on a six-hour repeat. You'll drive your neighbors nuts, but you'll invigorate thousands of runners, shaving days off their collective time.

Many runners will wear a name tag to get personalized cheers. Don't be alarmed if they give you strange looks the first mile or two -- they will have forgotten what they're wearing and will wonder how you know our names. For the next 10 miles, however, your cheers will likely be met with small waves and enormous gratitude. After that, they'll be too delirious or exhausted to acknowledge you much. Don't be hurt. It's not you, it's them. (No, really. I mean it this time.)

What should you expect of marathoners' delirium? Around Mile 18, the hallucinations begin. Runners will pass a mile marker and 10 seconds later forget where they are. By Mile 20, your running friends will start forgetting your name. By Mile 22, they will be forgetting their own names. But keep cheering, now more than ever. Rooting them on will be like singing lullabies to the comatose: despite no evidence of comprehension, it somehow, in one of the great mysteries of the universe, gets through.

Fuel
Officials provide plenty of liquid throughout the race, so setting up your own water station may not be worth the work. However, if it's hot, some runners will welcome a gentle mist from a garden hose. Just make sure you're not creating a slippery water hazard, and don't shower the entire street, in deference to the runners who would prefer to stay dry.

Late in a race, some runners like a little salt to fend off cramps and hyponatremia (a sometimes-fatal water intoxication), so a plate of small pretzels would be a good thing to offer.

Run, rabbit, run
If you're a runner yourself, feel free to hop in and accompany a friend for a few miles once the pack has thinned out. Join them in Greektown and you can have yourself a nice little 10k. They'll appreciate a pep talk, and your fresh legs can help them maintain pace. If it's windy, you can try running close in front of them to create a draft, just like in NASCAR.

Two caveats: Bring your own Gatorade and energy gels, and be sure to peel off by Mile 25. Crossing the finish line is an emotional moment, especially for first-time runners. That 48,888th stride brings an exhilarating release second only to the joy of giving birth. (Not having given birth myself, this is mere conjecture.) Don't diminish it by horning in.

All's well that ends
Spend a few minutes at the finish line. Pay close attention to the following times: 3:10, 3:15, 3:20, 3:30, 3:35, 3:40, 3:45, 3:50 and 4:00. These are the times that runners, depending on their age and gender, will be shooting for to qualify for the exclusive Boston Marathon. Witness the ecstasy of 3:09, the agony of 3:11.

Last year, watching the 5-hour runners struggle to finish, accompanied by cheesy Enya music and a hokey announcer, I wept. Until then, I'd never in my life had a cry that didn't involve a death or a spanking. Watch an amputee cross the finish line and you, too, will bawl. You might even pledge to start hitting the running path yourself.

Buckingham Fountain will be sorted by runners' last names, so it's a good spot to rendezvous, but encourage your runners to take their time stretching and getting a postrace massage before coming over. Make sure they know you won't expect to see them for at least 30 minutes after they finish. If they're much longer, you can check a medical tent, where computers track anybody who's reported problems.

Most runners will have stashed their postrace necessities in their gear-check bag, but there are a few extra things you should bring for your friends and loved ones. Hugs, for instance: hard to fit in a bag, but better for rejuvenation than any banana or bagel. Cameras are good to have on hand, as are cell phones. Runners will want to call either their parents or, depending on their condition, their chaplain.

Buckingham Fountain also is fertile ground for missed connections. Offer a massage to the right handsome, foggy-headed stranger and he'll be putty in your hands -- especially if you can help me remember my name.