Emma and Johnny are very into playing with water at the moment. One of the less messy ways they play with water is to put some water (less than an inch) in the bottom of a small bin, place the bin on a bath towel, and give them a range of things to play in the water with. Here they have a toothbrush, small medicine syringe, a couple of small containers, a toothbrush (not one used for brushing teeth), and a couple of spoons. They can spend hours transferring water between containers using the syringe and spoons, and sometimes they turn the bin into a wash station for their dinosaurs and cars.
An even less messy way to do this is to set the activity up inside the bathtub – then any water that spills goes straight down the drain. And, of course, those of you lucky enough to have nice weather can do this outside. We set it up on the floor so that I could keep an eye on them from the computer. =)