The basics, and of course they may vary for airline or hotel partner:
Dine where you haven't eaten a la RN / iDine before, spend $25 or more, rate the dine within thirty days, earn 500 miles (combinable with other offers, such as ALL DOUBLE, NO TROUBLE).
Registration required, bonus offer ends 30 September 2010.
Thread here for discussion and different programs. (Existing several posts have taken up residence there).