The Football Playbook for Windows and its "digital collection of tactical puzzles" which strips football (American soccer) to its barest essentials is now free. The game packs 42 levels where the player must get the ball from the goalkeeper to the striker. It's one of the greatest "sports" games I've ever played, as it emphasizes tactics and puzzle solving.

For a better overview of the gameplay, check out this earlier post when the game retailed for 4.99 GBP. The team told us that they made the full Windows version free because they are planning to update and port the game to mobile and tablet markets.