Sometime is difficult to get a group together to play. These games are either exclusively solitaire, or have a solitaire option. Solo play is a great way to understand the game, improve your play, and test your scores against other players on the web. There are so many board games with solitaire capability that the website www.boardgamegeek.com has a Top 100 Solo board game list updated each year!
The Isle of Cats
Exit: The Forgotten Island