Wobble board

This is my wobble board (sometimes also referred to as a balance board).

This is the piece of gym equipment which I use more than any other. 

I stand on it, almost all day, while I'm working. In this way, in getting a bit of a workout, almost all the time. 

It wobbles in all directions, which makes for a nice challenge. It's not too high of the ground, so it is pretty safe if I lose balance. 

In addition to just standing on it, it can be used for push-ups and planks, giving your core an extra bit of a workout.

All in all, I'd say that this is a great piece of equipment.