I'd recommend the mnt. bike and spd cleat idea for sure. You could even wear the shoes to and from the class if you want and not have to swap shoes once you're there.

We host an informal (but still brutal) spin class at our house every Tue and Thurs. through the entire winter season (from time change to time change) and it's 'B.Y.O.T.', or beg borrow or steal a trainer once you get here if you don't have one. A good friend of ours sets up the music and workout routines, and the rest of us show up and hurt. There's no way I'd have the discipline to do it regularly if it wasn't happening in our own garage, so it's a benefit to us and all the others who show up. Best part is that it's casual, fun and free. Most folks are on Kinetic Road Machines, and one of the guys was nice enough to loan me some resistance rollers that I've been using for a while now and REALLY enjoying. Sometimes the guy leading is even on rollers. Impressive coordination to lead a class, change music, follow the clock and bark commands all while riding rollers. Good times.

The freedom to work as hard or easy as you like can be dangerous. It's possible to truly flog yourself on the trainer, but it takes diligence to make it happen class after class. You just have to do it, even though nobody will know if you don't.

-Jeremy