Rubik's Cubes

There are many videos and tutorials available, but here are my favorites.

3x3 Directions -

4x4 Directions - Solving your Rubik's Revenge

If you are looking for a good, basic speed cube, we use DaYan ZhanChi or DaYan GuHong stickerless cubes in class.  I highly recommend stickerless cubes so that you do not need to worry about replacing the stickers when they start to peel.  There are MANY other good cubes out there. I buy most of ours via Amazon.