Churchill Solitaire - The most diabolical version of solitaire ever devised. Played by Sir Winston himself. Available via the AppStore and Google.
Tanglet - Tanglet is a single player word finding game based on Boggle.
Microsoft Solitaire Collection - Play Klondike, Spider, Freecell, Pyramid, and TriPeaks! Plus, Daily Challenges!
Crosswords Arena - Word game, multiplayer and computer players
Treys - Like solitaire... but fun!
Quackle - Open-source word game similar to Scrabble. Features a board editor, analysis tools, and artificial intelligence that rivals the best players in the world!