Fun, if you like that sort of thing:

http://www.brain-fun.com/Brain-Teasers/EinsteinsRiddle.php

Oh, and don't be intimidated by that 98% thing. It's way too easy to be that hard. That's either a misquote, he was flat wrong, or we just get more education on solving multiple systems these days than back then.

It was just a weird kinda sudoku. I used the same methods I use to solve those, made a grid on a piece of paper and went at it.

http://www.puzzlersparadise.com/page1034.html

Tons of logic puzzles! I've done a bunch of these out of boredom. :o :o