Someone once estimated that more computer time has been spent on Solitaire than on spreadsheets. (OK, I just made that up.) But most phenomena have causes, and Solitaire is one of the most addictive games ever created for the same reason that gambling is so popular: sporadic reinforcement.
This is the classic version of Solitaire. You start with 7 piles of cards, on each of which only the top card is face-up. You must sort them into suits, starting with the Ace and continuing to the King, in the 4 piles shown at the top right. You can move Kings to empty piles, or any card onto the next higher card of the opposite color. Cards are dealt 3 at a time from the remaining deck.
You can play using the keyboard or the mouse, or both. Preferences allow you to relax the rules a little to make it less frustrating.