It doesn't matter whether you're a goalie in soccer or in hockey, reaction time is the key to success.
Chelsea goalkeeper and Belgian international Thibaut Courtois recently showcased his super human reflexes by taking part in a drill that both tested his reaction time and his ability to not just say "nah, I'm done with this." The game is simple (but not really). All Coutois has to do is catch the balls that are thrown at him and correctly place them in the bucket that corresponds with the colour of the ball.
Honestly, by the third ball we're pretty sure we would be ducking for cover. We know Courtois is a world class goalie in the game of soccer, but you would have to think that this drill could still be applicable to hockey goalies as well.