Mark,
Lots of cool Apps listed on this thread.
I enjoy Shazam and use it quite a bit to identify new music I like and don't know the name of the title.
http://www.cigarasylum.com/vb/showthread.php?t=18767
I use CBS Sports and Yahoo to track my Fantasy Football teams.
I also use "Around Me" quite a bit when out of town.
I can go on and on as I have 11 pages of application on my phone.
For sheer fun for only .99, get Moron Test.