I got stuck on California Screamin in September- It was due to a cleanup effort (and train transfer off) for the row behind me. Can't tell whether it was the car in front of us that had a sick person, or the affected row, but someone made a really bad smelling mess.
I did, however, get to hear the evil music loop. I wish we could have been stuck on the MCBR though- that'd have been great. Instead, I get a view of the final helix, and a nifty concrete wall. And a bad smell.
Other than that, I got to walk off Test Track in '01, we got stuck on the area with the "DIP" before the tunnel, and got stuck on BTMR when the fireworks were running.