The best thing you can do is screw with them, to get back at them. My brother got a call the other day from a jackass telling him he was from Microsoft and they detected he had a virus. The guy wanted my brother to go to a site, ya da, ya da. My brother acted as though he didn't know anything about computers, having trouble following the scammers instructions, etc, and screwed with the guy for about 20 minutes. He recorded the conversation on his phone, and listening to the guy get frustrated is amazingly funny.