Both Eddie Murphy and Martin Lawrence became known for, along with being very funny, the characters they create. Murphy with the Nutty Professor characters, demonstrates serious acting ability while creating laughs. They don't do that so much here, but these guys age from mid-20s to 90s convincingly. Their love-hate "old married couple" bickering will leave you in stitches.
The rest of the cast is as underappreciated as this movie is in general. They're hilarious and memorable. I've been repeating Bernie Mac's lines and the "cornbread" scene for years. Casting R. Lee Ermey as the racist bad guy was genius too.
Watch this movie please, and if you've seen it watch it again. I was prompted to write this review having just seen it uncut for the first time. While the edited version delivers the plot well enough, you'll laugh along with the theatrical version much more. They're "keepin it real!"