I've had my iPhone for a few weeks now, but only within the last few days did I start to download a few silly applications like the Zippo lighter (looking forward to the next time someone asks me for a light) and the light saber (Nobody tell my sons about this.) I also downloaded Google Earth.

Now, I'm curious about other -- preferably free -- iPhone applications. There are so many that I find it a bit overwhelming, and I don't really have the the time to peruse 'em all. So, you got any suggestions for awesome, time-sucking iPhone apps?