Welcome to Fluther.
Seriously? This sounds like one of the worst ideas in the history of ever. You’ve heard of trolls, right? How do you propose to avoid their suggestions – since what you’re setting up, once people realize it – is a real-life “Truth or Dare” with no recourse to the person proposing the truth / dare scenario. So eventually the dares will be “to run naked in the road”, “to rob a bank”, “to make yourself a doormat for some lower form of life”, etc.?
If YOU want to propose several alternative challenges that you’d be open to and have people vote on them, well, that’s another thing. (It’s still too self-indulgent for my taste, but I realize that I’m out of step with a lot of younger people. In my day we set our own challenges and lived our own lives for our own purposes and didn’t broadcast it, ask for others’ approval or votes, and just got on with it. But I realize, sadly, that those days are past.)
Even better, if you just want to live your life and write about it, that would be about the best that I could ever hope for.
But hey, you do you.