I've been experimenting with different types of interval training and I'm curious to see what other people find effective.
The one's I do most are 3 minutes on, 3 off, 3 times. Usually I'll do 3 sets of those with 8-10 min rest in between. I also like the 1 min on, 1:30 off, 10 times. I will usually do 2-3 sets of those with 8-10 in between.