Here's some fun things you can do at an airport which will not only amuse you, but will also have the added topspin of getting you very urgently arrested.
Anyway, these are pretty inexpensive, which is good, because you'll likely need a small fortune for bail money.
Drink a bottle of tequila, and then lay down on the moving walkways and look at the ceiling go by. When you reach the end, simply roll over onto the other one. This will be seriously cool.
When security is distracted, place a bag on the conveyor belt and walk away before anyone realizes you did it. In the bag, you should place an alarm clock and some ordinary road flares. What a riot! You'll do serious time, for sure.
Have a large assortment of Civil War characters paged to the courtesy phone. Ask for J.E.B. Stuart, Robert Lee, and so on. If the services representative is a history major, simply comment on his or her obvious and unexpected employment success.
Start petting your suitcase reassuringly, and talking to it like a nervous dog.
Step onto the baggage carousel and ride it as far as you can. Just before it heads back into the restricted area, step off and move onto the next one in line.
If you're at a small municipal airline, go up to a ticket desk and request an unbelievably exotic ticket, like round-trip tickets to Kathmandu. This works even better if the airline is really tiny: good indicators would be names like "Des Moines Regional Airlines," "DC Beltway Airlines," or "5th Ave To 8th Ave Airlines."
If a fellow traveler asks you how to get to the baggage claim area, give him very specific directions on how to get to the air traffic control tower.