Thanks to Youtube a lot of unaired TV pilots have been popping up lately. I've found a couple that are worth a look.
Heat Vision and Jack was a pilot directed by Ben Stiller back in 1999. It starred Jack Black as Jack, an astronaut who becomes super intelligent after inappropriate exposure to sunlight, and Owen Wilson as the voice of Heat Vision, a motorcycle with the brain of Jack's unemployed roommate. The series, had it been picked up, would've followed Heat Vision and Jack as they travelled from town to town solving mysteries and outrunning NASA assassin/actor Ron Silver. The pilot makes Star Wars look like an epic.
Lookwell was created by Conan O'Brien and Robert Smigel and starred Adam West as an out-of-work actor who becomes a detective (at least in his own mind). The pilot was made in 1991 but has the look of a campy 70's cop show. Unfortunately both of these concepts were way too ridiculous to ever make it onto network TV.