Here's a favorite, seriously. It's aimed at the "prepper community" (isn't that that we're about, though in a different meaning than the usual?). But it is stuffed with tips, tricks, hints, ways to get by on less, ways to make something out of nothing (or out of something else that doesn't work any more)....there's new material every day. The name of the site says it all:

http://knowledgeweighsnothing.com/

Remember, what's between your ears is ultimately what will get you to the Gulch.

Lumosity looks to be the highest-profile puzzle site, not free but very good. May I now self-servingly mention the best-kept secret but totally excellent puzzle site, http://www.gamepuzzles.com -- "Gamepuzzles for the joy of thinking". Mind candy, math as art, epistemological paradigms. Designed and made by an Objectivist. See for yourself.

lol.

these are interesting. I'm going to definitely check out the speed reading one. thanks.

Very cool.