If you happen to be in San Francisco, like adventures and would like to make a quick buck, something you'll want to check out is the 'HiddenCash' account on Twitter.
HiddenCash is now hosting a scavenger hunt across San Francisco and dropping hints where you can find hidden envelopes filled with cash. Although the whole thing is still pretty mysterious, it's apparently a social experiment being conducted by an anonymous millionaire real estate developer who decided to share some wealth in the name of fun.
HiddenCash puts out cryptic tweets and leaves these cash-filled envelopes out in the open, with instructions to tweet and follow HiddenCash for more. So far, some people have remarked that they've been able to stumble upon a hundred dollars first thing in the morning—it's kind of like The Amazing Race with less travel, although the gratification is pretty instant and lots of people have the chance to win.