One I've been getting lately, every couple or 3 weeks I'll check the voicemail on my home phone and find a message from someone with a heavy Indian accent telling me they are from "the enforcement division of the IRS and I need to call them or a warrant will be issued for my arrest with law enforcement". I got one that had a computer generated voice calling herself "Rachel". I get a good laugh out of these, I even save the messages to listen to when I need a laugh, but regularly I'll see something in the police report in the paper where someone got taken by one of these calls for thousands of dollars.
I've also got calls from Indians telling me they are from Microsoft security and my computer is infected and sending out spam, and he is going to help me. I try to drag those calls out to waste as much of their time as possible. Mess with them like tell them I have dial up and need to get off the line, and can you call me on my cell. I proceed to give them the FBIs phone number to call me back on!
Then there are the auto extended warranty pests. Last one asked me the mileage of my 09 Challenger, I said about a million miles. They questioned that, I said I commute from Chicago to LA every day, miles really add up.... Have a nice day they replied and hung up on me.
Not so funny though when you hear about how much money these crooks con people out of.