I previously told you about TripIt, GateGuru is another cool travel app I found out about by talking to a guy who made it, a fellow attendee at a recent wedding. GateGuru tells you the location of food, shops, etc at all the main US airports, so, for instance, you know if you should grab a bite before you go through security or if you can wait and hit the brewpub past the evil TSA. I recently used it to find a real seafood place in my terminal when we had a long layover in Houston on our way to Buenos Aries, and a great greasy spoon for breakfast in Chicago on the way to Jackson Hole, my most recent trip. You can select an airport, or use GPS to figure out the one you are currently in. Cool stuff.
Also, TwentyFour! is a fun, addictive, and challenging math game app that a friend made. You race against the clock (or your buddy) to take as many sets of flashed four numbers that you have to add, subtract, mult, or divide with all four numbers to get 24 as you can, with extra bonus time for every one you get right.
Check 'em out.