So you've installed a rainwater collection system, and there are barrels and barrels of rainwater just stacking up all over the place. Man, you have so much rainwater, and the kittens are tired of drinking it. They are waterlogged with sloshing bellies. You'd better get more kittens, thirsty kittens who can drink up all that rainwater.
Or you can do something sensible with it. Here are some practical ideas for rainwater usage: