Dood : The Puzzle Planet - A strategy puzzle game for the smart ones
Trivia for Google Chat - Team-building w/ fun quizzes, games right inside Google Chat
63 - 63 is a race against the world.
Icebreaker from Range - Start your meeting with 200+ free team-building questions
Decode Me - Solve internet puzzles for mystery prizes
meet.atSlack - Team building on Slack