The Mental Floss team publishes a bimonthly magazine for 'knowledge junkies' and has also crafted some books, all with the following concept: bits of trivia - be they historical, scientific or cultural - creatively combined and brought to boil with a sense of humour. I am a great fan of this recipe that allows you to dip in and get a quick fix even when on the run. They also have a site that offers you some perfectly free factoids, though beware - the sneaky bastards are trying to get you hooked.
If you want to test your newly acquired knowledge, there is an online quiz to do that with: Jellyvision's You Don't Know Jack. The questions are oddly twisted, which makes hearing them and the possible multiple-choice answers as satisfying as actually getting them right. Beware though: if you fail to do so, the snarky host will mock you.
Now get out there kids and remember: learning is fun, fun, FUN!
Ps: if you have kids, you might want to introduce them to the nicely illustrated Horrible Histories series, which teaches history in an infotaining way. Just so they know.