Let me begin by saying you have to love Jerry Stiller to love this movie, because he's in just about every scene. And he's the Jerry you loved in Seinfeld, as well as many other incarnations. He's loud, he's rude, and he's hilarious. This movie would not have worked with anyone else in the lead role.
The idea of the film is that Stiller is the ultimate independent film producer, Morty Fineman. His movies may not be great art, but there sure are a lot of them. One of the best gags in this film is to just sit back and enjoy the titles for all the films. A lot of work went into conjuring up literally hundreds of titles--some of which will make you laugh out loud. To catch them all, you should check out the very well-done companion web site...
You'll probably enjoy this movie best if you're in the 35-45 age range, because it will take you back to all those drive-in movie classics you loved as a teenager.