Quoted from randomc's episode 6 writeup :

[Mizushima and Aikawa] have already proved themselves adept at translating unusual source material to anime by the brilliant job they did with Oh! Edo Rocket , which was adapted from a stage play by Nakashima Kazuki (who also wrote Gurren Lagann ) [...]

I generally barely notice exactly who the creative staff behind anime works are, but this is a set of connections that genuinely startles and impresses me.

(One interesting note is that according to ANN Mizushima also directed Hanamaru Kindergarten , which had a startlingly interesting set of ending animations that are well worth tracking down on their own; each one did its own little mini-story in various genres, complete in a minute and thirty seconds or so. I didn't watch HK itself, but I quite enjoyed the ending segments. I believe you can find them on Youtube.)

For future reference, ANN entries for Mizushima , Aikawa , and Nakashima .

(In another interesting thing, Nakashima not only wrote the original stage play of Oh! Edo Rocket , but he also wrote the script for one episode. I wonder how odd it felt to be scripting his own work as filtered through someone else, since Aikawa was 'series composition' for OER.)