customizing tshirts?

[lisadarling.livejournal.com]

after having looked through my boyfriends closet yesterday, I realised that there were a lot thsirt I could customize for me.
usually, I just re-make them into my size, (what was referred to shrinking earlier in this community) but now I want to do something more fun, something more challenging.
anybody has a good tip on what to do except the regular glitter, glue and paint?
I've tried the "custom Heidi" thing but those shirts can't survive even one washing..