Bottleneck is a coordination game for groups of up to six players. Several groups can participate concurrently.
Each group needs one bottle. You can use any kind of bottle, filled or unfilled. The task might be harder (or easier) depending on the type.
The bottle is standing upright on the floor. The groups then get the task: put the bottle upside-down, so that it is standing on its neck. But: you may only use your feet for that! Do not touch the bottle with your hands, or any other part of your body, except your feet!