The ToorCon 14 Badge shipped with RfCat firmware and a USB bootloader installed, so conference attendees were able to start experimenting with just a USB cable, a laptop, and the RfCat software. Although I am a fan of software defined radio, sometimes a wireless transceiver IC is all you need to do some interesting things, and RfCat is the easiest way I know to get started.
The badge is designed to be similar to and firmware compatible with the CC1111 EMK (aka "Don's Dongle"), but it has a few extra goodies. Most notably, it shipped with RfCat firmware and CC Bootloader installed. It also features a GoodFET compatible programming header and a row of test points that would have been compatible with the GIMME had I measured correctly. (Oops! Aren't you glad there is a USB bootloader?) The badge also has an option to install an external antenna connector, allowing better performance across the whole frequency range of the CC1111 than previous designs.Root the Box team built a multi-user wireless chat system. They implemented their own network protocol, user interface, and even HTTP tunneling from the ground up using RFCat's rflib Python library. (in two days!) Check out my video of the demonstration they gave me. They even posted the source code for their winning entry.
These were the same guys who won the ToorCon 13 badge hacking contest by implementing a simple game with 2.4 GHz wireless connectivity. Check out their Root the Box CTF event coming up in January!