Threadless.com has ongoing contests for t-shirt slogans and designs. I'm getting totally carried away with the slogans. Some of them I'm even proud of.

My current favorite:
Ask your doctor if Beyoncé is right for you.

Runners-up:
Owl Dirty Bastard rapped about drive-by hooting.

When I grow up, I want to be a human resource.

Guns are as American as condors, bison and passenger pigeons.

War is Peace. Ignorance is Strength. Guns save Lives.

Guns save lives, except when used as directed.

Ask your doctor if Shakira is right for you.

Whosoever believeth in me shall blah blah whatever.

For God so loved the world that he gave blah blah whatever.

Do unto otters as you would have them do unto ewe.

My nurse says Thorazine is a journal about the god of thunder.

My other t-shirt is a Trans Am.

Why would a good God damn?

More human than resource.

And I seem to get a decent amount of votes with simple clichés taken out of context or song lyrics like:
Go figure.
I found out the hard way.
Not that there's anything wrong with that.
Lend me some sugar; I am your neighbor.

Here's a page with all my submissions. You can't vote for them on that page, apparently, but you can go to their front page and vote on random selections there.