Twitch is finally ready to launch its first game after months of testing. The free karaoke-style title Twitch Sings will debut worldwide today (April 13th), giving you a chance to belt out tunes for a large audience. While there is an offline mode, the game is designed from the ground up to involve an entire Twitch channel. Streamers can invite broadcasters in for duets, while viewers can request one of the 1,000-plus songs, cheer to start light shows and issue challenges (say, singing like they're underwater).