Having a summer birthday, or even when they have a few friends around on a warm summers day is a great opportunity to let them have a water fight. It's definitely a 'more the merrier' game. And I have been astonished to have more than one young visitor who has never had one. Imagine.

They don't need fancy big water guns. Any plastic container will do. A hose is great fun, although you might consider limiting the time they use it as they use huge amounts of water. Also, you need to be sure they play fair as it can often be the cause of fights over who turn it is!