FUN FACT: The ecosphere is actually extremely bad for the shrimp inside of it. Unless you're going to change the water somehow, the ammonia build up over the course of time can kill any regular fish in just an hour. And all of that over years? That's just plain cruel. Look it up.
Ecosphere: This seems to be the original seller: http://eco-sphere.com/cart2/catalog/index.php?cPath=25 but it's cheaper to buy from Amazon: http://www.amazon.com/EcoSphere-Closed-Aquatic-Ecosystem-Sphere/dp/B005IZOB5M (This one is round, but you can find other shapes if you look around)
Gömböc: http://www.gomboc-shop.com/standard-gomboc.html
Gallium: http://www.mcssl.com/store/gallium-source/gallium-metal
Miracle berries: http://www.thinkgeek.com/product/ab3f/ (U.S. only, but I love ThinkGeek and want to support them) Here is a shop with a few other things, like the actual plant: http://shop.mberry.us/collections/all
Ferrofluid: http://www.amazon.com/Ferrofluid-Science-Project-Assorted-Magnets/dp/B00126LZD2/ or an alternative: http://www.thinkgeek.com/product/f025/?pfm=Search&t=ferrofluid%20magnetic%20display
Gigant microbes: http://www.giantmicrobes.com or http://www.thinkgeek.com/product/6708/?s