SteamVR has launched alongside HTC Vive today, and there are plenty of games available to get you started.
Some of the games and experiences are free, other will cost you, and there are demos available. Along with Vive offerings, those expecting their Oculus Rift in the mail at some point can purchase game for that headset as well. If you were lucky enough to receive your's in the post, have a look at the list.
The SteamVR pages contain dozens of titles and experiences along with Valve's The Lab which is a free VR game compilation. At present, there are 139 offerings across six pages.
HTC Vive started shipping today, and the $799 package comes with VR controllers, room scale movement, and an HMD featuring a built in camera. Also, for a limited time, those who have or plan to purchase a Vive will receive a free copy of Tilt Brush, theBlu, and Fantastic Contraption.