Aerogel - Wonder Material

Aerogel truly is a wonder material.  Lighter than air and has the lowest heat capacitance of any known substance.  I personally haven't found a project for mine yet, but just holding it in your hand with a flame over it is cool enough.  Here's a link to the DIY make your own at Aerogel.org.  But if you just want to buy some, you can get a sample disk over at ThinkGeek.com.