Real or elaborate put-on? It's hard to tell when Andy Kaufman — comedian and performance artist — is involved. In the early 1980s, Kaufman engaged in a series of absurdist exercises whereby he wrestled women and declared himself "Intergender Heavyweight Champion." Such bluster soon caught the attention of professional (male) wrestler Jerry Lawler, who challenged Kaufman to a match and proceeded to pile-drive him into the mat twice, thereby injuring his neck.
The pair appeared on Letterman's show in June 1982 to hash it out, Kaufman taking an aggrieved tone and Lawler assuming an arrogant, lackadaisical pose. In one of television's more shocking commercial lead-ins, an exasperated Lawler stood up and slapped Kaufman in the face hard enough to knock him off his chair (at about the 5:00 mark in the clip above). When the show returned from break, viewers witnessed Kaufman lose it, cursing and throwing a cup of coffee at Lawler. It was all very entertaining. But many have claimed that it was staged — just another Kaufman goof.