Last week my unit began the Mt. Everest Challenge. It's a cardio based program that challenges teams of 4 people to climb Mt. Everest. It occurs of 7 weeks and 1 day. It also measures % of body weight lost during that period.
The way it works is this. You'll get your four man team together, and then weigh yourself the day before the challenge starts. You and your team will measure how much cardio you do on a daily basis, granting 3 points per minute of working out. Each point is equal to one foot of the mountain. Each team member is allowed to do 600 minutes per week, at which point every minute beyond is only worth 1 point (this is to help mitigate the effect of workout freaks).
At the end of the period you will again weigh yourself, and compute the % of weight you lost. Each % point you lost is worth 250 points/feet. The goal is to have a combined point total between the four of you of 29,029. I really wouldn't suggest this program if you aren't in "alright" physical condition already, but it's a very good program to help push yourself over a good length of time to really better yourself.
Last year I did this challenge I lost 6% of body weight. I ended up gaining most of it back after my surgery since I was pretty limited on what cardio I could do for a few months. This year my goal is to get to 175lbs by the end of it, which would be a 7% loss (started at 188). Did a combined total of 90 minutes of cardio today. It's a big step up from what I was doing, so i'm hurting a bit. I'm hoping that by the end of this though I'll be able to knock out 90 minutes a day without any issues at all.