What are some high impact short-term actions for people who don't want to make long commitments?

Traditional EA recommendations and I aren't a good fit. Any job outside of a few narrow types of work I enjoy would drive me insane, and to preserve my mental health I've chosen to neither earn-to-give nor apply to work for an EA org. (Not that I'd be qualified for that; I didn't have the patience for much schooling either.)

However, I am still interested in finding ways to improve the world. So I was intrigued by this post on challenge trials; spending a couple weeks getting sick is something I could definitely do.  And now I'm wondering what other opportunities there are like this. Things that don't require a large commitment to monotonous labor nor extensive background knowledge or qualifications, yet can still have a significant positive impact.

Any suggestions?