Here’s a cool VERSABALL Beer Pong robot by Empire Robotics:
The core principle behind VERSABALL is the jamming phase transition of granular materials. The green ball is filled with a sand like material. When air is pumped into the ball, the ball softens. The ball is then pushed against the target object. Pulling air out of the ball jams the sand like material together, causing the ball to harden. This transition from soft to hard creates the gripping forces.
Via Hacked Gadgets.