Klondike Solitaire
The patience everyone has played: seven piles, four suits, one deck.
Seven piles on the table, the rest of the deck in your hand, and four empty foundations to build up from ace to king. On the table the cards come down instead, alternating red and black, and an emptied column takes a king. Not every deal can be won, which is part of why it has outlasted every other card game on a computer.