Reddit mentions of ThinkGeek Portal 2 PotatOS Science Kit

I'm fairly certain that it is in reference to the game Portal 2, where for a large portion of the game the "evil" AI from the first game becomes attached to a potato much akin to the potato batteries that may or may not have been a popular science fair experiment when you or I were children. (You can even get a potato science kit here: http://www.amazon.com/Portal-2-PotatOS-Science-Kit/dp/B006P0ET1K)

It's basically an apology for the poor quality, but there is an actual reference there.

For a little more background: http://knowyourmeme.com/memes/im-a-potato

I thought I would take a look and see why type of figurines were out there - came across this guy. Might be a good back-up if claptrap falls through...

Baking soda + vinegar (volcano?) Potato battery!

But seriously, there are some great ideas already here.

I would just call it density - will it float? You might want a bucket and some rocks, wood blocks, things of similar size. Then ask them to hypothesize (!) if another thing will float, make them easy, like a tarantula or a loaded handgun. Don't use ice ;) Layers of liquids is way cool too as someone suggested.

Conservation of momentum with hot wheels cars.

Properties of light with mirrors, look, it's backwards! And another one makes it right again! Flashlight goes over there!

Bug collecting. Insects vs. arachnids. What is alive and why?

Oh, kitchen, sorry. Ummm the one with the egg that sinks/floats in a glass of water when you add .. salt I think. That one looks fun. here: http://www.experiment-resources.com/salt-water-egg-experiment.html

wisd0m's thread is what you want.

This is as nerdy as it gets!

I hope it cheers you up some!! Turn that frown Upsidedown deary!