When I can't get out on my road or trail bikes, I alternate between a roller trainer and a recumbent exercise bike with programming for hills. Last year I watched mystery DVDs (the TV in front of my trainer has a build-in), and the whodonit aspect kept my interest throughout the 60 minutes that I put in. My latest discovery, however, is foreign language films with subtitles. The combo of reading/watching staves off boredom. It's also broadening to see viewpoints and lifestyles of other countries.