It may not fit the Webster's definition of what a 'good film' is, but somehow this film has always entertained *me*. I love Ringo Starr, young Dennis Quaid, and Shelly Long as our protagonist cave-dwellers. The stop-motion effects are fabulous: it's like a Ray Harryhausen comedy.
Of course "Caveman" is stupid, but in its defense, it shamelessly acknowledges that. It's better than recent fare such as "Encino Man", the "Flintstones" movies, "10, 000 B.C." or "Year One", which I wasn't even able to finish.