One of my personal favorites is when Dean Kamen got hit in the head with a soccer ball
https://www.youtube.com/watch?v=OnE0j69_gYk
Also a shameless plug for my team when our robot smashed full speed into the tower. Ehh guess that's not really the best of things to plug but it's fun to watch.
https://www.youtube.com/watch?v=pk8ZBIsJOv4