1.7.2 was deemed the update that changed the world, and with good reason. In addition to completely re-doing the biome generation code, and by adding double the biomes, Mojang also included a very cryptic option in the settings menu, appropriately titled ‘Super Secret Settings’.
This option will allow you to view your world in a completely new way by utilizing different shaders that add effects to your game-screen. While these are not at all practical for long-term play, they can act as fun little diversions and add a new level of challenge to the game. Here’s some examples of these different shaders in action: