Let's all take up a challenge. This challenge is to save $1000 in one year. Starting today. You need to post this on your facebook and twitter "I am taking the $1000 in one year challenge. Help hold me accountable and help me save $1000 this year). Then check in to various money saving things every time you do them: I walked instead of taking transportation, I rented a movie instead of going to the movies, I cooked my food instead of going out, I didn't get that $5 coffee that I was craving. Calculate the amount of money that you saved and transfer this to a new bank account. When that bank account reaches $1000 you win!
I think having a concrete goal in a realistic timline is very important. If you leave it up to everyone to make their own goal, then it's harder to track people and it also gives them a reason to not do it (I want to, but I can't figure out how much to put for my goal).