Alright. I think I'm officially certifiable. I have done as much as 5 hours on the trainer.
I also watch movies or series of movies, eg all the Indiana Jones, all the original Star Wars... I also take a short (<5min) break every hour to get off and stretch.
I play games with myself on long rides, like switching gears every 5 min and adjusting my cadence to keep my speed or HR the same. I do a lot of form drills, standing drills, all kinds of stuff just ot mix it up.
Now that I'm working more on power, I've been using spinervals more and I like it, but they are tough. The longest I've been on the trainer this winter season is 2 hours.
The trainer is fantastic for a quick 30 recovery ride. Helps loosen everything up, makes you feel better and it's over before you know it.
Living life like there's no tomorrow.
http://gorgebikefitter.com/
2007 Look Dura Ace
2010 Custom Tonic cross with discs, SRAM
2012 Moots YBB 2 x 10 Shimano XTR
2014 Soma B-Side SS