Somebody was telling me that speed skating develops your muscles better for road and track biking than mountain biking can. I never understood this and assumed they were ********. For staying fit during the winter CX skiing will pump your cardio to the max and is heavenly compared to slaving away on a trainer, despite what muscle groups are used. Too bad I live downtown so theres no good CX skiing around...

Actually, I remember staying at a friend ski chalet a few years ago and he had an exercise bike we would put on the balcony and spin like crazy on until we became huge steam vents. It was pretty fun actually, but we always moved on to beer pretty quick.