From Dec. 1 – Dec. 31, 2015, log 15 meals with a serving of Avocados on MyFitnessPal for the chance to win one of 6, $500 Under Armour gift cards. Users can only log 6 meals per day. Any type of avocado found in the MyFitnessPal database counts toward the Challenge. You can log your avocados on the web or on the app.

Read the full legal rules here.