Browse the Bookstore

This is the last and only place people buy magazines anyways. So pick em up before Apple buys all the bookstores and shuts them down.

Eat

Might as well since you have to pay $10 for a packaged sandwich in flight.

Drink

There's no shortage of bars at the airport. A scotch before the flight can knock you down cold and save you from the poor inflight service.

Get pitched

If you are a VC, you can invite geeks at the airport to pitch you by using Gowalla or Foursquare.

Look for an electrical outlet...

and when you find it, charge your smart phone (so you can play games on flight), charge your notebook (you know, more games when your phone battery dies) and read a book.

Call People

You know those folks that are NOT on your quick dial? This is a good time to call them for a quick chat. Just don't tell them you are at the airport!