There is always the possibility of trying to create a business. You can spend Bitcoin on server hosting, software developers, and marketing guys, and try to make Bitcoin by providing something unique that people didn't know they needed.
All of the above can be purchased with Bitcoin, which is very cool.
Than when the business is up and running smoothly, BAM create some sort of premium services and charge a small fee for usage of these.
True, there is always room for improvement on existing businesses.
You can buy Bitcoin securities, e.g. ASICMINER. See the Securities subforum under Marketplace.
I don't understand are these securities traded on an exchange? Didn't even know these existed until now.