I have one that says "I stole this shirt from a homeless guy. Why he had a shirt that says this, I'll never know." always brings out a chuckle, I'm not a big fan though. then I have one says "Without ME it's just aweso," which people struggle to understand. I prefer picture shirts though.
hehe i've seen tons of funny ones: "It won't suck itself!" and "It's nipple lickin' good" (on a woman's shirt!) and "Beer is technically a vegetarian meal"
When I was a kid my Dad had a shirt that said "Once I thought I was wrong, but I was mistaken" seemed hilarious at the time. My fav shirt is one that (and probably only the Aussies will understand this) says Common Filth Bogan in the Commonwealth Bank logo style. Also, my brother has this shirt that says "I am completely naked under this shirt"
I have a few one says " I don't want to hurt you but it's still on my list" "I came here to chew bubble gum and kick ass and I'm all out of bubble gum"
I have afew. I have one where it's literally to hands motioning to have sex (index finger goes through index and thumb hole. I have a shirt that has a picture of the world being covered in oil, with the words "BP" on the earth. A t shirt with albert einstein sticking his tongue out. A shirt that sais community college, a random shirt with a tiger on it. Im a t-shirt and jeans kind of girl.
I've got one that says "Make Today Special: Share a joke, hum a song, pass some special joy along. And if someone should come your way who doesn't share your joy today, the hell with 'em!" I found it at the Goodwill some time ago and couldn't resist picking it up!