Lots of good choices . . . I'll try to add a few that don't seem to have been mentioned yet:
The Valley of Gwangi - This was a "serious" movie starring James Franciscus and Gila Golan, with special effects by Ray Harryhausen. Think wild-west cowboy shows . . . gypsy curses . . . and dinosaurs.
Caveman - A comedy with Ringo Starr, Barbara Bach, John Matuszak, and Shelly Long. (Ever see a tyrannosaur get a hotfoot?)
Our Man Flint and In Like Flint - These movies starred James Coburn as Derek Flint, an American superspy who out-Bonded James Bond.
The Ambushers, The Wrecking Crew, Murderer's Row and The Silencers - Based on Don Hamiton's books, Dean Martin plays Matt Helm in these four movies.
There was a movie called something like The Fearless Vampire Hunters . . . I remember a scene when a vamp was about to bite a woman, who held up a crucifix in defense. The vamp's reaction? "Oy vey, have you got the wrong vampire."
Has anyone mentioned Animal House or Stripes yet?
Or the Scary Movie series? (These cheesy flicks are not for viewing in polite company!)