I've just realized that VOY was the only series not to have a wild west episode.
TOS: Specter of the Gun
TNG: A Fistful of Datas
ENT: North Star
DS9.. OOPS that's embarrassing, somehow mixed this up with Back to the Future III which makes this a post about a whole lot of nothing.
DS9 and VOY were the only Treks to not have a wild west episode.