I've never gotten a fake IRS call but I've gotten fake ones about credit cards, mortgages, car warranties, etc. I avoid most of them by not answering unfamiliar numbers to begin with.
ETA: Just thought of a fun one from a year or so ago. Apparently, there are people who scrape real estate/rental listings on sites like Craigslist and Zillow, and put up their own versions, impersonating the owner/seller. Usually, they will sell the scam by saying they're out of town and just need you to send them your deposit/downpayment/whatever, and they will send you the keys.
I got to the point of this guy asking me to mail him the deposit, and it was at that point I started googling around just to make sure this was legit. It wasn't. Turns out this same guy had done it with dozens (if not more) properties, scamming people left and right. Many of them gave him their money.
I reported it to the FBI Cybercrime division, and also let the real owner of the house know someone was running a scam based on his property. (He didn't care--he was quite rude to me about it.)
ETA: Just thought of a fun one from a year or so ago. Apparently, there are people who scrape real estate/rental listings on sites like Craigslist and Zillow, and put up their own versions, impersonating the owner/seller. Usually, they will sell the scam by saying they're out of town and just need you to send them your deposit/downpayment/whatever, and they will send you the keys.
I got to the point of this guy asking me to mail him the deposit, and it was at that point I started googling around just to make sure this was legit. It wasn't. Turns out this same guy had done it with dozens (if not more) properties, scamming people left and right. Many of them gave him their money.

I reported it to the FBI Cybercrime division, and also let the real owner of the house know someone was running a scam based on his property. (He didn't care--he was quite rude to me about it.)