Thanks for the input, everyone.

I do lube my pedals periodically (and had done so quite recently), and I also had the tension adjusted pretty loose (well, loose enough for the 99.99% of the time when I can THINK to twist my heel in time, although I generally don't have to think about it). Maybe I could set them a little looser, but I really think it was the straight up & forward thing that did it. Without the reaction time needed, looser still wouldn't have helped.

The multidirectional SPD cleats sound perfect - thanks! At least, the picture of the package would indicate that straight up would release? I'm not very concerned about unintentional releases - I'm not really that hardcore (just hardcore enough to hurt myself ). I found a review of the SH-56 cleats, and that person mentioned using them to get back on the bike after a broken ankle, so that makes me feel better.

Cool - something to ask for for Christmas. Not planning on mountain biking any more this season, so maybe by next May this will all seem like a bad dream.

By the way, I have Crank Brothers Quattros on my road bike, and love them. Sounds like you got duds, Aggie. Of course, they shouldn't have bent under a 180 lb guy, either. I would consider Eggbeaters or Candies or something but I'm pretty sure I would have had the same problem. When I said "additional release angles", I meant up and down, and not just side to side. Sorry - I was unclear.