Create the circle of life... in a condom! This ecosphere, similar to ones developed by NASA, will last a reasonable amount of time if left in indirect sunlight during the day. Very fun and maintenance free. Fishtank and focal point of desk!

EDIT: DO NOT ATTEMPT! POSSIBLY DANGEROUS FOR ANIMALS!

Condom Ecosphere Vid
Click play to watch. Thanks all, took a lot of work.

Step 1: Watch Video.

Start off by opening and cleaning condom with water. The thinner the condom, the more easy to see through, but the weaker.

Step 2: Pour Gravel, Plants, and Snails

Pour your gravel, your plants, and your snails into the condom wit water. Use a funnel or make one out of a bottle (as shown in video). Be gentle as this is when you are most likely to pop the condom.

Step 3: Add Fish

Add your fish. I like to use neon tetras because they are small and won't eat the adult snails.
Make sure to hold the lip of the condom, as it will want to lose grip as it fills with water.