 LUFA is a third-party free software (MIT license) USB protocol stack for the USBKey and other 8-bit USB AVRs.The RAVEN kit supports wireless development using Atmel's IEEE 802.15.4 chipsets, for ZigBee and other wireless stacks.It resembles a pair of wireless more-powerful Butterfly cards, plus a wireless USBKey; and costing about that much (under $US100).