The Sky Mall magazine they have in the pouch in front of you is a great way to waste time while waiting for the airplane to take off.
There are lots of crazy things that are easy to make fun of.
Depending on the length, you might want to bring something to do (exc. gameboy, laptop, magazine, coloring books?) I remember I was stuck when my friend took out his gameboy and I had nothing. On the way back we played Worms Armageddon and Truck Dismount on a laptop.
Before you leave double check your bag before you leave your house and make sure that there isn't anything you wouldn't want the security guards to find. Going through the metal detector is no big deal. Some, if not all, airports do random searches. If you don't have anything the security guards wouldn't like, it should be no problem. Every security guard is different. My sister's bag was searched and she was afraid they were going to take her Tech Fusion (279) button. They didn't.
Have fun on the airplane. These are people you most likely wont ever see again. Make conversation with people around you.