Need cooling on the go? Instructables user imjasonc shows us how to build the most portable air conditioning unit we've seen, powered by USB and built in the case of a Brita water jug.
It uses the same principles as most other DIY air conditioners: place a fan over ice-cube-cooled water to blow freshly cooled air. A Brita jug is perfectly suited for this purpose, giving you a big reservoir for iced water and a small casing in the top (where you'd put the filter) for the fan.
The fan is powered by a USB cable, and it's easy to pick up and take wherever you want to go (plus it's easy to clean). Hit the link for the full how-to on wiring the electronics.
Build a Discreet USB Air Conditioner with a Brita Pitcher [Instructables]