skootles:
I double checked my connections and it turns out that I didn't have the MISO and MOSI reversed on the UNO. I had them reversed on the ATtiny, but not the UNO.Of course, I shouldn't have had them reversed on the ATtiny because the library reverses the mappings already. Whoops.
What did you mean by the role pin though?
Glad you fixed that
Just looking at the standard ping example at http://maniacbug.github.com/RF24/pingpair_8pde-example.html
If you read the comments there is a section that describes how you set the "role" of the transmitter, and you should have one of each role so that you have back-and-forth communication.