Fun Math Sites
All work and no play makes all persons dull. Everyone has their own favorite web distractions (you know the ones I mean). Mathematicians are no different (for an example of our humor: What's purple and commutes? An abelian grape! —enter awkward silence— ok, maybe we're a bit different). While it's impossible to list all the FUN and entertaining sites out there, here's a starter list of some good ones. Some are just plain FUN, some are helpful, and some defy description. If you have a FUN favorite that's not here, email me and I'll see if I can fit in on this FUN page.
The joy of suddenly learning a former secret and the joy of suddenly discovering a hitherto unknown truth are the same to me – both have the flash of enlightenment, the almost incredibly enhanced vision, and the ecstasy and euphoria of released tension.
— Paul R. Halmos, I Want to be a Mathematician, Washington: MAA Spectrum, 1985.