Apparently some study found that the difference between people with bad luck and those with good luck is that people with good luck take lots of low-downside risks.
Can't help with specific suggestions, but thinking about it in terms of the decision-theory of why it's a good idea can help to guide your search. But you're doing it for the action-feeling...
Climb a tree.
r/Fitness does a weekly "Moronic Monday", a judgment-free thread where people can ask questions that they would ordinarily feel embarrassed for not knowing the answer to. I thought this seemed like a useful thing to have here - after all, the concepts discussed on LessWrong are probably at least a little harder to grasp than those of weightlifting. Plus, I have a few stupid questions of my own, so it doesn't seem unreasonable that other people might as well.