I was wondering if anyone has any experience with adding a wireless module to the digispark? I would like to have my digispark talk to the digiX when that comes in. I also see that nRF24L01+ modules are dirt cheap. I just don't really know where to start with this project.
Is the digispark's Attiny85 + 8k flash enough to run the nRF24L01+ with a mesh networking library?
Also, it looks like the wireless module required 4 pins, leaving only 2 free on the digispark, not enough to drive a RGB led 
You should be able to provide the CSN and and SCK signals from one pin on the digispark. From the SCK line, connect a diode followed by a small capacitor (I'd try at least 330pF) going to a transistor gate. Us a pullup resistor to pull the CSN line of the nRF high, with the transistor pulling it low when it is on. Before sending the SPI command, put the SCK pin in output mode high for a few microseconds to charge the capacitor and thereby pull CSN low. Then change the pin for SCK out, and send the SPI command. The SCK clock will keep the capacitor charged for the duration of the command. After the clock stops the transistor gate leakage will discharge the capacitor, turn off the transistor, and then the CSN line will go high. It would be best to do the RC calculation based on the transistor gate leakage rather than my off-the-cuff guess of at least 330pF. I've attached a (very rough) circuit diagram.
Another cheap wireless option is 433Mhz. I've seen 10 xmit/receive pairs selling for $20 on aliexpress. Only 1 pin required for tx and one for rx (or you could even multiplex tx/rx with a couple of diodes). They supposedly work with the virtualwire library.
