This isn't anime but I think this is related here.
PLOT: When evil threatens Akihabara, three "youths" (a Super Sentai otaku, a cosplay otaku, and a closet anime otaku) receive technology from a beautiful scientist to fight against it.
Basically it's Power Rangers with moe culture.
Here is the first episode.
EDIT It is unlisted in youtube so I can't embed it here.