Feed The Beast is a group of people that specialise in making high quality modpacks and maps for Minecraft. We started out as a custom challenge map in Minecraft that made heavy use of multiple tech mods.
It played very similarly to a type of map known as Sky Block, where the player is starts in a void world with only a small platform, and must overcome a series of challenges. Because FTB included tech mods, it was possible to use the various custom blocks and items to keep track of the challenges and the player's progress, as well as automatically give awards after each challenge was met.
The map was then adapted to allow multiple players to compete against each other in a race to complete the objectives. This version gained large popularity after being live-streamed on Twitch.TV with Direwolf20 vs Nearbygamer, both very well known users of the mods included in the map.
As the map was released to the public, it became apparent that it was very difficult to distribute the map file, mods, and configuration settings to those interested in playing it. At some point a decision was made to combine all of the mods into an easily distributable pack, as well as create a launcher that would streamline installation. These maps became extremely popular and in order to allow more people access to the maps the FTB Launcher was created.