I think that there's more to it than just marketing. I suspect that the NHL, in coming up with the schedule, tries to line up rivalry (or, at least, division) games on Wednesday nights because NBC's marketing interests are their own interests; then, NBC tries to cover as many of those as possible. More often than not, by my evaluation, the games shown are rivalries (more or less). When you have ~25 Wednesdays during the regular season, though, you're likely going to have some that don't really satisfy the rivalry criteria because of scheduling, building availability, broadcast rights, logistics and so on. I imagine that tonight is one of those nights. It's just a name tonight, but I think that it's more than just a name most of the time.