You must be aware about Sun SPOTs? I am not talking about the spots on sun star but palm sized battery powered devices which wirelessly transmit data regarding temperature, movement and sound. Now Sun has gone ahead and open sourced Small Programmable Object Technology or Sun SPOT platform code.

The hardware of the device, software and virtual machine has been included under the GPL V2 license. Also the company has come up with a SPOT software emulator for testing programming minus the actual device. Check the code out here.