I guess this is technically online money making, since you are using internet to make cash, right? I was in the airport today and made a few George Washingtons by selling my wifi signal through a mobile router. It's pretty easy to do. Just sit in the terminal, broadcast your wireless signal, and then sell your wifi access cheaper than airport prices with a wifi management software. If you do not have a hi speed mobile wifi card, you can also sell your regular GSM/CDMA internet access, but of course your bandwidth will be limited. Since it is Christmas travel season, I was able to clean up nicely with bargain internet seekers. Tip: Sell your wifi service in small time blocks, that way when you get on the plane, you don't have a bunch of angry chargebacks through your merchant account! Also, name your router something official, like "Cheap Dulles Airport Wifi" or something along those lines.