I'm working on join algorithms at the moment, so I spent the last few months getting up to speed on the latest research.

The rest is just from general interest. I spend around ten hours a week reading papers or textbooks. Whenever I find something really mind blowing I follow up citations, set up google scholar alerts for the authors, subscribe to their rss feed etc.

A lot of my favourite papers are linked on the OP site - it looks like a good place to start.