There were some tense moments on NBC's Today show this morning. While being interviewed by Katie Couric, out-of-control funnyman Robin Williams goofed and made a proctologist/colonoscopy joke. (Couric's late husband Jay Monahan died of colon cancer in 1998; since then, she has made colon cancer awareness and detection a major focus of her life.) Realizing his mistake, Williams quickly apologized. However, seconds later, he continued on his riff. No comment yet from NBC.