I’ve been wanting to start this site for years, finally doing it. Its not themed yet, but a bit of content is there: bTeaching.com – everyday ideas for learning and teaching. The idea is to capture teaching ideas, large and small, and relate them to subjects, age groups, philosophies, etc. Its not as formal as lessonplanet, the ideas can be informal descriptions of games you can play in the car as well as more detailed teacher-style plans. Its intended as a resource for parents, teachers and older kids, but not as a fully fledged curriculum source.
Check it out, and feel free to add ideas!