Speedrunning is a competitive time trial game in which players move through a predefined route in the fastest possible time. Speedrunning is popular in many other games and has been done in Antichamber since it's release in late January of 2013. There are a variety of different routes, called 'categories', that speedrunners 'run' with differing objectives such as completing the game, locating all the Signs, or locating all the Pink Cubes.
As Speedrunners attempt to minimize the time taken to complete each route, records are kept for status and achievement within speedrunning communities. The Antichamber leaderboards can be found on this page. Walkthroughs and tutorials on many of the routes are also kept here to encourage and assist beginners in entering into speedrunning.
Discord is similar to a merging of IRC, Skype, and Teamspeak. It has separate voice and text channels. The Antichamber Discord is available here. It can be used for general purpose Antichamber discussion, although it is typically used mostly for speedrunning discussion.
If you learn any of the routes and want to live speedrun race against others, follow these steps: https://dl.dropbox.com/u/21445444/srlg/SRLGuide.html After following those steps, you'll want to type into the chat "/join #antichamber" without the quotes to join the Antichamber chat channel. From there, you'll be able to talk to all the others who race it (if they are online). Alternatively, use the above Discord to message any of the runners, whether they are online or not.