Paul-Rene Jørgensen (a long time JIRA and Confluence customer, author of various useful Confluence macros and all around good bloke) caught his son studying up on Java Concurrency:
Advising startups is something I've started doing in the last year. It's a fascinating way to use one's brain
and experience to solve other people's problems.
I'm loving it.
Besides the few I advise, I've invested in one, HomeThinking.
HomeThinking provides realtor reviews, ratings and metrics (qualitative and quantitive) for home sellers.
I also make a lot of small microfinance loans to entrepreneurs around the world through Kiva. Read more about my on going Kiva Challenge (update).