I'll second Uphill Grind.....I love to hate it. The intervals are long, challenging and does seem to help. Hillacious is also good, but for some reason I look at it as being easier yet I'm equally trashed when it is over. Go figure.

I can't remember if I like or hate No Slackers. I'll let you know tomorrow--on Thursdays, I do a 35-45 minute Spinervals interval. No Slackers is in the rotation of three, but I can't remember which one it is. Besides Uphill Grind in the set of three there is one I like doing and one I despise and I don't know which is No Slackers.

When winter comes I actually like the 5 hour long century DVD. I only do 3 to 3.5 hour stints--if you go from the beginning it is easier; if you start up for the end, it is tough. But, you should be heading for summer so the shorter, painful ones are better.