Since I've been thinking for a long time about the project I would work on in the event of a sabbatical, my answers surprised me:
- Get better at teaching languages. Read lots of Hebrew and extra-biblical Greek.
- Go to [insert developing world country], and teach there.
- Read primary sources and classic secondary sources for the sheer joy of learning.
This feels like rest, a real sabbatical, a break from the academic "publish and perish" rat race and the pressure of teaching seven classes a year, a chance to rediscover why I entered this vocation in the first place. I also expect it would do more to help my teaching than the major writing project I actually proposed.
Along the same lines, this description sounds very attractive:
"I have come a long way from where I was at the start of my sabbatical. The one activity I chose specifically to take me away from my work has become a central part of my work and of my life. As a professor, I am required to make reasoned and thoughtful professional plans, but going where my heart (rather than my head) led me has yielded unexpected, rejuvenating, and inspiring rewards." - Dominick Scudera