Lexica - An open source word-search game.
LetsDraw.It - Guess and Draw, Drawing Battle, Pictionary, Copy picture - online drawing games where you can compare your skill with others.
Crosswords Arena - Word game, multiplayer and computer players
skribbl - Word guessing based on drawing.
Tanglet - Tanglet is a single player word finding game based on Boggle.
Drawasaurus - Drawasaurus is an online drawing & guessing game you can play with friends or strangers.