For a while I satisfied my idea-spreading urges by teaching math to talented kids on a volunteer basis. If you're very good at something (e.g. swimming), you could try teaching that, it's a lot of fun.

Or you could spend some effort on figuring out how to measure rationality and check if someone is making progress. That's much harder though, once you get past the obvious wrong answers like "give them a multiple choice test about rationality". Eliezer and Anna have written a lot about this problem.