Black Desert Online - This Korean developed MMORPG offers a dynamic, action-based combat system in a richly developed fantasy setting.
SpaceX Falcon 9 Lander - Try (and fail) to land Elon Musk's SpaceX rocket
NosTale - NosTale (The Tale of Nomads of Silver Spirit) is a totally free MMORPG that includes simple (but beautiful) graphics and also lots of class options.
SpaceVR - Explore space with Oculus Rift (pre-launch)
Runescape - RuneScape is 3D Action-Adventure, Massively Multiplayer Online, Role-playing, Fantasy-based and browser-based video game developed and published by Jagex.
The Size of Space - An interactive visualization of the universe