As we have several dungeons now i came to my mind that we could promote them in some way.
I'm speaking of an "event" thingy where people get recognition and are engorged to make dungeon runs. I would take some time and effort but we could have something like a reward/recognition/title to the group that showed the most team work or to a group of people that have come together for a dungeon for the first time etc.
Making weeks of "dungeon" may not a bad idea alto I'm not sure.
Something else would be a "chat channel" thing that is dedicated to people looking for a group.
Well those are my two cents I might be sounding stupid it's 3 AM here