I participate in a little mom's preschool co-op for my three year-old. On the day I talked about rain, snow, wind and water, our free play activity was my own "mom" version of a water table. Because the outside weather wasn't conducive to outdoor water fun, our fun had to be inside. Whether your looking for inside fun because the heat index is over 100, or it's pouring rain, or their is a foot of snow outside, tuck this little activity away to keep your little ones active and engaged.
I used two under bed storage bins, filled them 1/3 full with warm tap water, had a plastic watering can for each child, plastic cups in different sizes and measuring cups. If your kitchen isn't fully tiled like mine, consider setting this up in another location with a tile, cement or linoleum floor that can withstand getting wet. Even the garage would work in some climates. Just be sure you choose a safe location and monitor the amount of water on the floor so children can safely move around without getting hurt. 
Since I was doing this a preschool activity, I needed the kids to make it home somewhat dry, I used plastic store bags to make 'smocks' for each of them. I flattened out the bag and cut out a shallow C shape from the middle of the bottom 'seam' of the bag to make an neck opening. Leave 3 inches of the seam on both ends, these will be the shoulders of the smock. Next cut open both sides of the plastic bag all the way to the bottom seam. Snip the handles apart to create ties. This should resemble something like a scrimmage jersey.Slip their head through the opening in the bottom of the bag, and tie the handles securely at their hips.
If you're doing this at home with your own kids, swimming suits would make it extra fun, especially in winter!
Keep a stack of towels on hand, because try as they might, water will get on the floor and you'll want to wipe it up periodically so your feet don't get cold and wet and to keep it safe for them.
These kids played with this set up for a 30-45 minutes, with no sign of getting bored.To do this activity outside, prop the storage bins up on buckets or set up two folding chairs facing each other, using the seats to set the water bin on, making it accessible from both sides and would allow up to four kids to participate.
* * This activity requires constant adult supervision! Do not ever leave a child playing with water unattended. A child can easily drowned in just a few inches of water.
