The wizards at the Czech Technical University's Department of Control Engineering created a machine to show off how their servo motors can be used for precision tasks - and so they made it juggle.  Juggling is, of course, both easy and hard.  Anyone can do it, like playing golf, but doing it will is something else entirely.  Jugglers often have to move to keep the balls in the air because of subtle changes in throwing force and angle.  Not so this Juggler machine:



Robot shows off juggling skills