I'm also taking a sabbatical! I guess mine is also self study, although I never quite thought of it that way. I've taken this time to be able to have in-person lunches with many interesting people, work on open source projects, and sit in on seminars at the local university. I think I'm just beginning to learn how to access local resources for learning.

I'm also thinking of freelancing, and have been gearing up for contracts, and also to perhaps start an agency with a friend. I really value the freedom that has allowed me to explore my programming and math (and climbing/yoga/martial arts) interests these last few months.

One unexpected thing about my sabbatical: my social life is better, I have way more time and energy for it :)