Kerbal Space Program is a space exploration sandbox game — think Minecraft in space. Most folks assemble spacecraft and try to launch them without killing their occupants. Others, as seen here, build orbiting basketball goals and go for extra-vehicular dunktivity.
The first half of this video is someone lobbing what looks like Telstar 1 at the hoop — the bricks can be particularly brutal when the thing is travelling at thousands of meters per second and the simulator uses, like, real actual space physics.
Second half is where it's at. Someone builds a Dominique Wilkins Dunk Rocket and fires that thing at the goal, with predictable results. Might want to go for a finger roll next time, guys.