While I agree that some hobbies seem to be insane, for me, biking is much better for my health than listening to music/HT. I've lost well over 40 pounds and completed my first century (100 miles) through biking. I plan on losing another 40 pounds and completing several centuries this year. On the other hand, when I listen to music/watch movies, I'm much more likely to drink beer/eat bad food. Plus, I'm just sitting there in one place. I've since tried to watch what I drink/eat when listening to music, but it's a process where habits are hard to change. So, if I had to choose between biking and stereo/HT, I'd choose biking. On the other hand, I've spent way, way, way more money on my stereo system than on biking. When there are $1,000 interconnects, and a very, very nice bike costs $2,000, and you need several sets of interconnects (then there are power cords, speaker cable, DACs, the list goes on and on and on), biking ends up being much cheaper.