Rocksmith+ - Rocksmith builds off of the fundamentals of music games like Rock Band and Guitar Hero by offering fundamental lessons in actually playing guitar.
Stack Overflow - Community-based Q&A part of the Stack Exchange platform.
Osu - Osu is Music, Rhythm, Single and Multiplayer video game developed by Dean Herbert.
The Answer Bank - The Answer Bank is the UK’s leading question-and-answer site.
World in Audition - World in Audition is an Addictive, Dancing and Music Simulation.
Blurtit - Blurtit is a Q&A website. You can ask a question or answer on any question.