A text-speak acronym meaning "For The Extra Point"
Generally refers to obtaining some lesser victory affiliated with a greater one. More specifically, it can refer to performing certain specific actions in a video game which lead to some achievement or award beyond those offered for simply accomplishing a basic task. Also implies a certain guarantee that such a reward is part of the existing rule system will be and that it is not a random occurance (in video games, such random rewards are usually referred to as "Easter Eggs")
Translating this term from its football origins does not diminish its meaning. It merely extends the application.
In World of Warcraft, finishing the Culling of Stratholme instance is a commonplace event, but walking away with the Reigns of the Bronze Drake is FTEP.