GoodBooks.io - Largest curated collection of 8,500+ book recommendations.
Trivia for Google Chat - Team-building w/ fun quizzes, games right inside Google Chat
BookAuthority - BookAuthority collects the most recommended books on business, technology and science - as featured on CNN, Inc and Forbes
Flinkit! - Web-hosted team building games for small and large companies
Goodreads - See what your friends are reading.
Icebreaker from Range - Start your meeting with 200+ free team-building questions