you ain't gonna find much for a 2g, I'd suggest jailbreaking it.
Angry Birds works for 4.2 I think.
You should also try searching the apple forums, I did and there are a lot on the same subject on which people have listed working apps.
If I were you I'd just get an upgrade, 4g's are pretty cheap now I think.
[TPO][OSG][ARA][Zero] "and I have tons of friends" Deakster/Dickmaniac/Deak