Something of a Basara parody and Gintama gets meta (to the point of Gintoki reading the manga of the series itself, more than once).
Theres an Otsuu concert that involves her continuously singing “Ba Ba Ba Baa” or something similar.
Then theres a Basara parody with Shinpachi being represented as Shingen and Hijikata as Kenshin, the result is an otaku war.
Gintoki also goes meta and reads the Gintama manga.
I have no idea, looks like it’ll continue.