Bubble has some coloured plastic (vinyl?) bathshapes that are great fun for using outside of the bathroom too. You could make your own versions of these if you can't find any by cutting shapes from waterproof tablecloths or from sheets of PVC table coverings available at Lincraft or Spotlight. You could also use any foam type shapes as they will stick when wet like these do. This activity is also fun to do on a mirror, sliding door or the fridge/washing machine - handy when you are trying to get dinner cooked!