The Portable Dry Ice Maker ($500) allows you to make your own 1 pound blocks of dry ice anytime you want. You simply need to aquire a cylinder of compressed liquid CO2, connect it to this device, open the valve and watch as the CO2 fills the device's chamber, vaporizes, expands, freezes and becomes a block of -109.3° F dry ice in around 60 seconds. You can use dry ice for a number of things, including keeping food and beverages cold at parties (it doesn't melt like regular ice!), amazing people with cool science tricks, creating a smoking swimming pool or using it in other nefarious things we won't mention (er, ok see the dry ice bomb video below to see how not to use it).

Dry Ice In a Swimming Pool

Cool Dry Ice Trick

Dry Ice Bomb - What Not To Do