I have: Fight Club, Revolver, Hell Hath No Fury, Very Dark Place, Local Hero, Extra Shot: 20
Now that winter is here I have dedicated myself to doing atleast one every day. Needless to say they melt time away on the trainer. Only downside is that it can be very hard to continue doing them once you start to get worn out.
Honestly some of the best money I have spent on cycling, period.
(And I would say HHNF is probably the hardest so far, you tend to get to about 7 minutes into the 20 minute sections and you think: "WTF!? its gotta be close to done!" then it says "13:00", probably one of the most horrific feelings)