My Tracks is good if you like walking.
Etherophone is a good one for getting on peoples' nerves (or your dog's if you have one!).
Alchemy is a good game, as is Winds Of Steel. Talking Tom is a bit of fun.
I sometimes use Opera Mini, too, as I'm on 3 and they don't let you look at anything they consider adult (sniffpetrol comes under this). Using Opera as an alternative browser gets around this annoyance.