Shamrocks Solitaire
Shamrocks Solitaire is a solitaire card game where the player moves cards around 3 card piles. You can build cards up or down on these piles, and you don't have to worry about suit. The challenging part of the game is that you are not allowed to have any pile with more than 3 cards in it. Also when you've removed all the cards from a pile, you can't start the pile up again, so it makes sense to try and keep the bottom cards in your piles as long as you can.
Watch a Shamrocks Solitaire video tutorial