The Instant Insanity puzzle
by Mark Frauenfelder from on (#33D8F)
Puzzle designer Fleb takes a look at the Instant Insanity puzzle, which was patented in 1899. It reminds me of a cross between Rubik's Cube and sudoku.
I like Fleb's videos because he teaches you general principles of puzzle solving, not just how to solve a particular puzzle.