Shamrocks Solitaire is my favorite pile based solitaire card game. It's a lot of fun, and it's easy to learn. The one tricky thing is that you can't have more than 3 cards in any pile. All the piles start out with 3 cards, so the hardest part of the game is at the very beginning. Your goal is to build up all the foundations from Ace to King by suit. You can build the piles up or down without any regard to suit. Also like most solitaire card games if you remove all the cards in a pile you can't start that pile up again.