When you are looking for a simple, neat way to occupy your kids for a small amount of time, I have no idea what you could do. You should really ask someone else. When you are looking for a ridiculously messy and difficult activity that takes much more time than you have, then I highly recommend the "Dino Excavation Kit!"
We received one of these lovelies for Christmas and the kids have bugged me EVERY SINGLE DAY to "dig" into it (archaeologists are howling with laughter over than one, you can be sure). We decided to give it a try today because nothing else was going on and I thought it would give me a good opportunity to try out the new "Fancy Cam" I got for Christmas.
Adelaide and I opened it up and removed the cute little plastic hammer and chisel. I assumed they were mostly for show because these "fossils" would surely pop out easily. After all, according to the photo on the box, one good whack with a hammer and that baby will neatly crack into a dozen pieces. Still, I put our little square of plaster into one of our handy art trays to keep the mess to a minimum, congratulating myself on this stroke of housekeeping genius.
And then we hammered. We hammered and hammered and dug and chiseled and scraped and smacked for a VERY, VERY LONG TIME. Finally, the tiniest part of the first piece emerged. Addie was SUPER excited and also totally tired of actually doing the work. So, it was my turn. I pounded and pounded on that thing (with a plaster dust-covered toddler on my lap who continually tried to "feed" me chunks of plaster) until I'd had all the fun I could stand. Then, I made Aidan come upstairs and take over. He actually made some real progress because he has much more determination than the rest of us; and... because I totally loosened it.
Here's where the real fun started. As soon as the parts actually started to emerge, so did the screaming and fighting about who's turn it was. We decided on two-minute intervals so that one person could excavate while the other crumbled up plaster and rubbed it all over their clothes and my kitchen. Just two time-outs and one threat of physical violence later, the fossils had emerged in all their glory (except for the one I broke).
The kids assembled their Pteranodon while I wiped down the table, chairs, floor, faces, new camera and toddler. Then, I swept up all of the plaster crumbs, dust and mini muffin debris (that's another story).
A few minutes later, they had lost all interest and this gorgeous "museum quality replica" lay broken and scattered around the house. I can't really blame them, after all, Wonder Pets was on. Thankfully, each time I step on a piece embedded in the carpet, I'll be reminded of all the "paleontologist approved" fun we had. And, thankfully, I'll always have these professional looking photographs.