When I find something interesting but am feeling too lazy to look into it properly, I drag it into my bookmarks bar to look into at a later date. After a while, it gets pretty full (any relation to how lazy I am?) and they need sorting out. I thought it would be cool to have an extension that would act like stumble upon however only stumbling through my bookmarks, so being a developer I made one. The Chrome API docs had everything there for me so I dived in and created it in about an hour.
You can find the extension here: Randomarks
And I've put the source up on Github: https://github.com/eddie/Randomark
Overall it worked out pretty well, feel free to join in and send a pull request. Any suggestions or improvements mention me on twitter or leave a comment below.