Success has given Norm MacDonald a vault of oldies-but-goodies. There are joke gems from the comedian’s years on the stand-up circuit and his time on Saturday Night Live as the host of Weekend Update. There are also one-liners from his roles in movies such as Dirty Work and Billy Madison, and voice appearances on television shows such as Family Guy. All that has provided MacDonald with plenty of material — just don’t expect to hear it. “I just tell them ‘no,’” he says when asked how he handles requests for jokes or lines from a movie.

Actually, MacDonald doesn’t keep any material, no matter how funny, around for very long. His jokes, which he delivers in his signature nasally, deadpan style, have a two- or three-month shelf life, max. “[Because] it gets rote and it gets dull,” he says.

MacDonald also avoids memorizing material in order to ensure a joke stays interesting. He says it’s like telling a story to a friend and then having someone else walk in and ask you to repeat it. “You would change the story because the first person has heard [it],” he says. “That’s what I’m like, because I’ve already heard the story…So, I change it up to amuse myself.”

See MacDonald change his story in order to keep you — and himself — entertained at 8 and 10:30 p.m. today and tomorrow. MacDonald also performs 8 p.m. Thursday, and 7:30 p.m. Sunday. The Improv, 7620 Katy Freeway. For information, call 713-333-8800 or visit www.improvhouston.com. $30.

Thu., May 1, 8 p.m.; Fri., May 2, 8 & 10:30 p.m.; Sat., May 3, 8 & 10:30 p.m.; Sun., May 4, 7:30 p.m., 2008

This article appears in May 1-7, 2008.