Well, thanks to Google Glass, you can get a small glimpse of what it's like to be a world-class tennis player.
Federer played a a friendly match with Stefan Edberg (formerly ranked #1 in the world), and wore the glasses for the whole game.
"It was really fun shooting this video," Federer tells the Association of Tennis Professionals. "It's not often you get to explore new angles of watching tennis. I hope fans enjoy this new perspective."
Well, it's not every day we get to see what the game looks like from your perspective, Roger, so thanks for that. We have to go try and lower our heart rate after watching tennis balls come rocketing toward us now.