A Munchkin is the sort of person who, faced with a role-playing game, reads through the rulebooks over and over until he finds a way to combine three innocuous-seeming magical items into a cycle of infinite wish spells. Or who, in real life, composes a surprisingly effective diet out of drinking a quarter-cup of extra-light olive oil at least one hour before and after tasting anything else. Or combines liquid nitrogen and antifreeze and life-insurance policies into a ridiculously cheap method of defeating the invincible specter of unavoidable Death. Or figures out how to build the real-life version of the cycle of infinite wish spells.
It seems that many here might have outlandish ideas for ways of improving our lives. For instance, a recent post advocated installing really bright lights as a way to boost alertness and productivity. We should not adopt such hacks into our dogma until we're pretty sure they work; however, one way of knowing whether a crazy idea works is to try implementing it, and you may have more ideas than you're planning to implement.
So: please post all such lifehack ideas! Even if you haven't tried them, even if they seem unlikely to work. Post them separately, unless some other way would be more appropriate. If you've tried some idea and it hasn't worked, it would be useful to post that too.
If you are a human, then the biggest influence on your personality is your peer group. Choose your peers.
If you want to be better at math, surround yourself with mathematicians. If you want to be more productive, hang out with productive people. If you want to be outgoing or artistic or altruistic or polite or proactive or smart or just about anything else, find people who are better than you at that thing and become friends with them. The status-seeking conformity-loving parts of your mind will push you to become like them. (The incorrect but pithy version: "You are an average of the five people you spend the most time with.")
I've had a lot of success with this technique by going to the Less Wrong meetups in Boston, and by making a habit of attending any event where I'll be the stupidest person in the room (such as the average Less Wrong meetup).
Perhaps, but don't forget that a lot of research has shown that social interaction in general is key to health, long life, and social and mental well being. Having close social connections itself may be the most important thing, more significant then other peer effects.