I bought a 4-week membership to a CrossFit gym through Groupon last year. The "WOD" (workout of the day) portion was about 15 minutes long, but that wasn't the whole class. This particular gym had one-hour classes and my membership allowed me 3 classes per week (which suited me fine - this maxed me out and I found I didn't have the capacity to do any other workouts during that month). We would start with a 10-minute warmup, then do the WOD, then do 5 sets of heavy lifting for the Body Part of the Day (each set 8-10 reps, with 1.5 minutes' rest between sets), then 20 minutes of cardio (running outside, or rowing machine/stationary bike), then a cooldown.
The WOD was always written up on the white board on the main gym wall. There would be 5 exercises. We had to go through all 5, 3 times, as fast as we could, taking rests when we needed to but keeping them short, as we were being timed. One example of a WOD might be 10 jumps (or step-ups if you can't do jumps yet) up and down on a plyo box, followed by 15 pushups, followed by 20 walking lunges holding medium weight dumbbells, followed by 15 reps incline bench press, followed by 20 situps.
The Body Part of the Day would cover one of the major muscle groups. Typical exercises might be back squats, deadlifts or shoulder presses at a given percentage of your one-rep max (I don't remember the percentage they used anymore).
It was a great workout, but CrossFit seemed to be expensive - at least in my area - and anyway, I always find myself coming back to home video and Cathe.
Stebby