Credit for a good deed, as in John earned a lot of brownie points for doing his boss's report for him. The term originated with the points earned for various achievements by the youngest group of the Girl Scouts, called Brownies. In the mid-1900s it was transferred to general use.
n. imaginary credit for doing something well. (Originally “demerits” in railroading.) How many brownie points do I get for not frowning when you take my picture?