Paper and Pencil

Dots and Boxes - Dots and Hexagons
Describes the rules for playing on a squared grid and introduces a variation of the game.
http://www.drking.plus.com/hexagons/dots/

Eric Weisstein's World of Mathematics: Dots and Boxes
Provides the basic rules and explains different strategies for playing.
http://mathworld.wolfram.com/DotsandBoxes.html

The Games Compendium - Pencil and Paper Games
Descriptions of games that can be played in teams.
http://www.edinburgh-scout.org.uk/games/gc6.html

Mathematical Games: Sprouts
Brief summary of the game with diagrams.
http://www.madras.fife.sch.uk/maths/games/sprouts.html

Pencil & Paper Games Plaza: Tic Tac Toe
A simple explanation of how to play.
http://www.xs4all.nl/~spaanszt/PencilPaperGames/TicTacToe.html

Pencil and Paper Games
Instructions for playing Tic-Tac-Toe, Squares, Sprouts and Othello.
http://www.geocities.com/paper_games/

Pencil and Paper Games
Animated instructions showing how to play Sprouts, Pipelayer and Capture.
http://orion.math.iastate.edu/danwell/MathNight/ppg.html