My 21-month-old loves to play with water. For preference, she does it outside, in singlet and nappy, with dirt, mud, leaves and sand thrown in for good measure ;-)
When the weather is too inclement to allow for outdoor water play (a frequent occurrence in the past few months, with Melbourne suffering a long, cold, rainy winter and cold spring), I have taken to setting up a simple water station for her in the kitchen, on the slate floor. It's just a thick towel, two bowls filled 1/3 with lukewarm water, and a varied series of pouring tools - cups, jugs, toy teapots, measuring spoons, anything really that my Tupperware cupboard disgorges.
She really enjoys it, and her aim is getting better all the time - my days of removing saturated towels after 3 minutes are passing! She spends ages carefully transferring the water from one receptacle to another, often narrating what she's doing for me as I cook the dinner. It's a great way to incorporate some fine motor play and casual togetherness at what can otherwise be a rushed time in our day.