Kids love sandboxes. Sandboxes are big are big and messy (especially when there is no lid!) and they kill the grass they're sitting on top of.
When we first moved in to our house, we had a purple triceratops sandbox complete with sand, sand toys, and weird green stuff that the previous owners left behind. Our daughter liked it alot. All the other kids that visited liked it too. The lid was gone so it constantly got water in it- hence the green stuff. One day someone got so upset about water pooling in it when it rained (I guess we didn't get around to draining it quickly enough for their liking) that they dumped it completely upside down. Our backyard is open to the common area behind our house. The sand stayed around on the ground for a while and then eventually rejoined the earth, mixing with the dirt. The sand box ended up in a dumpster. Four years later, we now have two kids, the younger of which had never played in a real sand box. We visited the beach and she was in heaven. I kind of wanted to have a sandbox since she loved playing in sand so much. I didn't want another big sandbox taking up valuable real estate in our tiny backyard though.
Then it hit me! Make a small sandbox using a wide, shallow, lidded storage box! I already had a perfect storage box with lid. We already had some beach toys. All I needed was some sand. I bought two bags of play sand because I wasn't sure how much I'd need. If I had lifted it myself instead of letting the nice guy at the store do it, I would have known one was all it would take (I wanted the box to be portable!) For less than $4 I had a little sandbox. My husband, the smart guy he is, figured out that it would work well to put the sandbox on top of the little plastic outdoor table (another leftover from the previous owners) and have the girls sit on their little plastic Ikea chairs* (we've had them for a while, I don't remember how much they were, probably under $5 a piece). So it became a sand table. The girls love it!
*a quick search of Ikea's site and I couldn't find those chairs any more, maybe they will get some more (or similar) again later. You could probably find such chairs in a variety of stores actually.