I took the weekend tool school. I don't know what I paid -- not quite that, but I thought it was worth it.

The experience was very much what wnyrider describes except our lectures were intermixed with hands-on. E.g., learn about the brakes, now take them off, clean them, and put them back on. We had 4 students with different types of bikes. My bike was in terrible shape and so became the "Attention, class, this is what a bad bottom bracket feels like. Notice the grinding?" Well, except for nearly every part.

The cost of the class was the same as a complete overhaul of a bike. For my $300 hybrid, I'd never pay for a full overhaul, but for my learning experience, yes, it was worth it. I plan on doing it again this year with a different bike.