R
One I have had quite a lot of success from is "Does this rag smell of chloroform to you?"
some1 just link him to the original thread where people are going to be borrowing from anyway to post here
Best one: point at them asif you were louring them toward you, when they walk over to you say "if i can make you come with 1 finger imagine what i can do with 2"
A quick search later and voila. Really the thread of ruined chat up lines that GTA started is the best one to be looking at, there is some absolute genius in there.
The best chat-up line is, of course, "come with me - I've got a knife". Or, as posted, the rape one.

