> I think it was my Finnish teacher who told me a pretty good way of ending an annoying call. When you hear it's a telemaketer, just say "I'm going to leave the receiver on the table. Talk as long as you like.". And do so.

Or do that and don't tell them you're going to do that. A lot of them talk so relentlessly that they won't notice for a while, and then they're stuck with the bill for the completely useless call. Just don't forget to hang it up later.