Crystal had some good roles (especially in romantic comedies like "Forget Paris" and "When Harry Met Sally") but IMO he had a GREAT role.... that of comedian Buddy Young in "Mr. Saturday Night". While the movie is basically a comedy, it's also a great study of this sad character and how he relates to others (most notably with his brother, excellently played by David Paymer).
I started watching "Forget Paris" one night, thinking that I'd be changing the channel any moment, but enjoyed it. He was great as a referee, exchanging barbs with NBA players. And I cracked up during the scene in the apartment with the girlfriend's father or grandfather, especially when Crystal stood behind him with the kitchen knife.
I've never seen Mr. Saturday Night, which for some reason I alwys confuse with "Broadway Danny Rose." I'll be sure to catch it when I can.
