If you want to spend a little and make something cool, you could use a coolerdor with peltier units built in. You could use a scrap thermostat, scrap computer CPU heat sinks and power the whole thing with a solar cell and rechargeable battery pack.

http://www.customthermoelectric.com/tecs_imax.html

http://cgi.ebay.com/3-6-9-12-V-Volt-...QQcmdZViewItem

A fun idea, but the hardware will probably run you at least $100, and you'd have to have a few small power tools and little amateur know-how in electronics.