Half Minute Hero (TL;DR) version
Do the Time Goddess' bidding and save the world from destruction! Nice fun game that you can do in quick bites.
More in depth version
This is no doubt one of my favorite games in the library, and I highly, HIGHLY recommend it to anyone who likes Action games or Old School RPG satire. The game is about a boy who sets out to save a kingdom and, through a twist of fate, ends up making a pact with the Time Goddess to save the world...which only has 30 seconds until it explodes!
The game mostly parodies people, gaming, and most of all, the classic RPG, and it does it well. The game as a whole is really a parody, making it a point to "Grind, Grind, Grind!" when really getting to high levels only takes a few minutes. While the player only has thirty seconds to save the world, they can pray to the Time Goddess and, with an added fee, can turn back the clock. The story is expansive, and there are multiple paths and multiple endings, as well as multiple ways to go about each level (some story arcs even being surprisingly serious and tense).
And that's just the first mode. There are several modes, some of which tie into each other. This game will last you many, many, many hours, but the best part about it is that it doesn't matter whether you want a game that's easy to pick-up and stop at any point or one that keeps you in for the long haul, because this game occupies both of those roles. Really, I feel that this game should be in anyone's library regardless of whether they like RPGs or not. It's a great game, and for $9.99 it's a steal.