I was just googling roller workouts (just got a set) and saw this interesting quote:

"Two poker cards stuck in your spokes will give as much resistance as most people can handle when riding rollers."
http://www.ultracycling.com/training...ing_part2.html

I haven't tried it (I currently get enough resistance with big gears on my TravelTrac) but I may in the near future.

Anyone tried this or some other homegrown solution for adding resistance to a trainer which doesn't have a pricey fan or adjustable resistance device?