How do you brush up on your general knowledge?

I went out with friends one night this past week and we participated in a trivia game. I have been out of school for 17 years and I’ve realized that I have forgotten so much and I would like to brush up on trivia and general information. What’s the best way to do that? Do you ever do that?
Also, am I the only one who can’t post questions from the desktop site? I let the mods know, but I can’t remember if it’s a known issue.