Title: Kami-sama no Iutōri |Artist: Junji Ishiwatari, Yoshinori Sunahara, and Etsuko Yakushimaru |Show: The Tatami Galaxy
This is an ED that it takes a while to fully appreciate. At first, you might be hooked by the pounding rhythm, Etsuka Yakushimaru's entrancing vocals, and the nifty geometric designs. Stick with Tatami Galaxy, though, and you'll realize that this song and its visuals compliment the show's message and story very cleverly. I can't say much more, but I recommend you watch to appreciate just how outstanding this ED is (for an equally outstanding anime).
Until then, this is simply a great song to add to your playlist.