I'm sorry, the number you've reached is not in service

I had a scammer call me today. He told me he was with the US government and I've been given a $7,000 grant (gee, usually you have to apply for them first). I told him no thanks and hung up. Within two minutes he called back (I let the machine get it this time) and he said the same thing, except it was now a $12,000 grant and he would transfer it directly into my checking account, all I had to do was give him my account number. Really? Yeah and that prince in Syria's money will be coming in any day now. He's called back twice since.

How do you deal with telemarketers/scammers/political groups?