-aaaand.
Litchi Hikari Club - wtf. Really, seriously, wtf? God, I love this author. Note, all three additions are by him.
Bokura no Hikari Club - the shota-ish prequel which explains so much about the Litchi Hikari Club. Not that I need much explained this early in the storyline...
And finally, the one I know least about, but it totally doesn't matter because it looks hella awesome:
Innocents Shounen Juujigun aka La Croisade des Innocents - "So basically, this is like LHC got copy+pasted into the time of the crusades. And it's longer." -scanning people said that. I say this: It's just like the Hikari Club manga, except it's during the Crusades, and God is like "Hey y'all!" and there are no Japanese Nazis.