For my quadcopter project, I needed to figure out a way to control it. Many people just use an off-the-shelf TX/RX system for RC cars and planes, and there are many 2.4GHz versions of these, but I wanted to try something custom. While reading this thread on the RCGroups forum, I noticed the author kept talking about wireless capabilities integrated into his MSP430 control board. To do that, it uses the CC2500, a 2.4GHz RF transceiver module. This little device only needs a couple of decoupling capacitors and an antenna to operate, and has a convenient SPI interface. Using the diagram from this PDF, I designed a PCB for me to try.
When I acquire more funds, I will get the PCB made and report back on how it works. For now, here is the layout in EAGLE.