Online logic puzzles and games

Puzzles.COM - Logic Problems Weekly and monthly interactive and printable puzzle

200+ science experiments explained in cartoon format

Hunkin’s Experiments - These are my kind of science experiments–short, sweet and to the point in a very un-scientfic format.

Tips, tools, tricks & hints about math

CuriousMath - a fun site with lots of tricks and handy tips.  My favorite page is The Top Ten.