Just name it -- something you want to see solved but hasn't been yet. Political, technology, scientific...anything.
I hope to spark a discussion like the original version of this topic - http://news.ycombinator.com/item?id=442571. More importantly, maybe someone will do something about your problem.
Alternatively, put some rats on Seth Roberts's set-point diet (aka Shangri-La diet) and figure out the path of action, then develop it in pill form for those of us where Seth Roberts's diet didn't work / didn't work well enough.
To make a lot of money, ask yourself where people aren't looking. Often the place they're not looking is a place of moral blindness. Plenty of us would pay just about anything to look normal. The moral blindness part is the people being sanctimonious about fat being a sign of weak willpower and having no concept of the actual science involved.
Another place to look would be fast, accurate molecule recognition array tests for venereal diseases. Get it down to something the size of a vending machine, $20, and thirty minutes (results sent via text message) and you'll get people paying you every night. Again, moral blindness may be a reason why people aren't looking as hard in this direction as they should to create lots of hedons - sex is sinful.
Speaking of not looking where everyone else is looking, would it be too crazy to ask people to do something that actually creates large amounts of value instead of throwing sheep? Even if it involves doing something other than computer programming?