Biking IS addictive!!! In the bad snow we get in Michigan I've learned to just get on the trainer. I've tried other exercises, but nothing gets the heart rate up and keeps it up for me as much as cycling. I've tried aerobics, which I hate, and karate, which nearly ruined my feet, but the only workout I really enjoy is cycling. If I don't get in at least one 3-4 hour weekend ride or a couple of hour-long weekday rides I get REALLY grumpy. The trainer isn't much fun, but at least it's cycling. It helps to put the trainer in front of the TV and watch a movie.