I need a slogan first, and I want to let everyone here participate so we have a 10 or more, 20 or more, 30 or more, up to 50, I need ideas for low cost prizes (my boss is a tightwad) and ways to win them, and a catchy slogan I don't like anything I've come up with

Slogans are hard, but I've got some prize ideas-
giftcards for the amount of weight lost (10lbs = $10)
A paid vacation day
office parties
A new DVD
Weight loss gagets that will aid in working out (those big yoga balls, weights, jumpropes, sweat bands, water bottles, etc)
Healthy recipies cook books
Kitchen utencils, Salad bowls, etc etc
A really cheap idea: a wear your PJs to work day (depending on where you work)
The prizes can be given out by 'who lost the most weight at the end of the week/month' or you can win them by seeing who can run the fastest mile, do the most pushups, etc.
some slogans - (this is really hard, and mine are lame!)
Summer Shape-up
Weight-loss workplace
Work-for-weightloss

Let's Get Fit!
Spring Into Weight Loss Action
Hop Into Healthy Habbits
We're A Healthy Office (or whatever type of place you work at)
Try gift certificates for $5 or $10 dollars
Maybe some sort of body wash, pamper me thing
A book on maintaing the weight loss
You may want to come up with A Healthy Diet plan for those who don't need to lose weight, but maintain it. Since you may have people who are thin or whatever like the person above me mentioned :)
Hope this helps, it's all I can come up with :)

Lose 50lbs in minutes! Cut off your legs!

We just started a challenge here at work...there are 12 of us.
We have a wide range of starting weights...high of about 300+ to low of about about 150ish. Everybody has a different goal.
The one thing we did to try to make it fair is to use a percentage basis (not pound for pound), i.e., if I weight 200 lbs and loose 2 lbs and one of my co-workers weighs 100 lbs and looses 2 lbs, they have won (based on % lost).
As an incentive and for a prize: Each person put in $20 when we started. If you gain any week, you pay $1 for each pound or portion thereof gained if you stay the same you pay $0.50, if you are going to be out of the office for a whole week and can't weigh, you pay $2.00.
We started a month ago and everybody has lost something! I'm sure it will get more cut throat as we get to the end (scheduled to end in June).

It doesn't sound fair to me...I'm already skinny so there is no way for a person like me to win this challenge...!!!!

Slogan - "Lose some weight you fat bastard!"
Prizes - Pies, lots of them.