I think I enjoyed Mel Brooks movies more when I was a teen and in my twenties to be honest, but I still find most of them watchable and a few even still retain quite a few laugh out loud moments. He tends to run certain jokes into the ground over the course of a movie, but that's easily forgiven because fresh gags just keep coming and coming.
While I enjoy History of the World, High Anxiety, Spaceballs, Blazing Saddles, and all the rest, I have to say I find Young Frankenstein is my favorite. For those not in the know: Young Frankenstein tells the story of the grandson of the Doctor Frankenstein who created the original monster. Frederick Frankenstein is a well-known doctor who inherits his grandfather's castle and work. The film was shot in black & white and is pure comedy.
The cast is outstanding and I can't imagine anyone other than Gene Wilder playing the title role. Marty Feldman plays Igor (perfect casting and he's a riot throughout) and a very young Teri Garr plays Wilder's assistant. Madeline Kahn, Cloris Leachman, and Peter Boyle round out the primary cast. Gene Hackman has a small, but memorable part as a blind man who has a funny and entertaining interaction with the monster played by Peter Boyle.
I think the movie holds up well considering it was made in the early 1970s. If you're put off by black & white, you should reconsider and give this a chance. Films in black & white have such depth, and for a movie like this, the decision makes complete sense.
If you liked Gene Wilder in Willy Wonka (the 1970s version, not the crazy Tim Burton version, of course), you'll like him in this as well: Sane one moment and completely off his rocker the next.