A phrase one says when horribly losing in a video game, and in a last ditch effort tries to pull off a comeback, by inspiring their teammates. Wither ends in epic fail or epic win.
When all towers were down in LOL and the team was losing 20-10 in kills Bob yelled out "FOR NARNIA!!!" and his team promptly lost the game 20 seconds later.
Short-hand for the word floccinaucinihilipilification, meaning the estimation of something as valueless (encountered mainly as an example of one of the longest words in the English language).