Monthly Comic Magazine HERO'S in Japan is currently offering free a preview of the latest Gurren Lagann spin-off comic on their site. The comic is titled Tengen Toppa Gurren Lagann Otoko-ippiki hen and it places Kamina as the main character in the story that is set in modern-day Japan.
With an original story by Nakajima Kazuki and GAINAX, and serialized by Nonoyama Saki this spinoff was first offered as an anthology of drama CDs in Japan. In the comic, Gurren Lagann characters become students at Dai Gurren Gakuen. The top page linking to the comic is in English, while the actual comic is in Japanese.