There are various stock exchanges and the like cropping up but very little in the way of any real investment going on right now, here's some ones I've been probing lately but I'd wait until something as decentralised as Bitcoin comes along because these all look like they can get taken down easily.
https://btcjam.com/ - You can lend coins to people here
https://cryptostocks.com/ - This stock exchange has been up for awhile now without being taken down
https://1broker.com/?m=3 - You can trade options here, this looks to be one of the more legal ones but you do use margin when doing it, it works like forex trading
https://a-ads.com/ - If you want to get into advertising at all, I recommend Anonymous Ads, a good way to get ads onto peoples sites without annoying the fuck out of visitors
There was an stock exchange called GLBSE awhile ago that got taken down because of legal problems, either it was fraud or something else but I don't know much about what happened, we're going to need a lot of decentralised stuff that is peer to peer otherwise these sites will probably get taken down too.