Each box contains the pump, the Wubble, instructions and a plastic measuring tape that ensures you inflate the Wubble correctly. You can also buy wubble ball refills which come without the pump.
I can imagine Wubble ball would be fantastic at a festival bouncing over the crowd. In fact, Wubble is just fantastic tactile fun. It is hard to describe what Wubble feels like or is even made off, but I would highly recommend you get one for some fun of your very own.