I don't think rollers are fun, but if you are wanting to keep biking during the winter without freezing, the rollers are ok. I usually put in a DVD movie and watch that while riding my rolllers. I did the Bourne Century last winter, to put some miles on on a weekend day while it snowed all day long.
I will put in a DVD ride for whatever miles I want and then do something else. It is great exercise and being on rollers is a good thing for improving your riding skills and there is resisitance, because if I stop pedaling, the bike stops in less than two seconds. It is not like coasting on the road, you always have to pedal.
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2007 Jamis Ventura Comp
2006 Jamis Explorer 2.0
2000 Specialized Hardrock (bought used)
Swim, Bike, Run and sounds like fun