Sherman the Giraffe is voiced by rapper MF DOOM. There's also a song on his Dangerdoom album named for and about the show.
Coiffio sounds like Carl doing a really bad Japanese accent.
Keep Circulating the Tapes: For a time the only way you could get the episodes on DVD was on Adult Swims make your own DVD website, after it got taken down the only way to even get the pilot was on a bonus disc in the Adult-Swim-in-a-box collectors set. While it still has yet to be released on DVD, as of March 2014 the first 6 episodes have been released on iTunes and as of July 2014 they are all on their official website.