Much has been already been written about Cavemen, from better writers than me. In case you don't know, this is the show based on the successful series of GEICO ads with the cavemen living among our time. It seemed like such a no-brainer, given the success of Mr. Whipple's World in the 70s, and the more recent successes of Noid Patrol and Where's the Beef Now?.
This was a very early candidate for worst show of fall 2007, but I'm pleased to report that the powers that be have managed to make a show that's actually not the worst of the year. (Big Shots, I'm looking in your direction...). It's not good, but it's not nearly as bad as you might think. It pretty successfully sets a tone not at all unlike other comedies where a particular class of people, normally looked down upon, have to live among those who normally do the down-looking. Its closest analog is The Munsters, but I think it has just the slightest hint of Jeffersons.
It has a couple of things going for it. Nick Swardson was hilarious in the first episode, and the character of Nick is pretty funny. However, I don't understand why, with the bigger budgets that a series allows, the makeup's worse than the commercials.