Usagi Yojimbo is one of my favourite comic series. It's run for many years and is up to volume 27. I am awaiting volume 26 to read and then I shall have read them all!
Not part of the series (I suppose) is a one off book called Space Usagi which follows the adventures of the origial Usagi's far distance relative IN SPACE!
The hierachy of feudal Japan is somewhat replicated with space castles and cyborg ninjas and Usagi now has some blasters as well as his samurai sword. It's pretty adorable.
The one thing that happens (which hasn't happened in 25 volumes so far) is that Usagi get's a girl but she is sadly killed later on. That is future Tomoe, who I adore in the regular series. Aside from that sad moment, the whole book is good fun. Future Gen also shows up (again as a mercenary type) and helps out in one of the adventures. There is also a hilarious moment where past-Usagi gets zapped to the future for an hour, just in time to help future-Usagi destroy another mechanical ninja. It's farsical but still fun. It was cool to have duel Usagi's for a few pages.
I think other than the Teenage Mutant Ninja Turtles cross over I am almost out of Usagi Yojimbo! I don't know what I'll do then - it has been such an excellent year reading them all.