A few friends and I have been doing something similar to this for awhile. Each week, a different person shares a playlist, that they find interesting. It might be a genre sampler, a theme, or just stuff that they've been listening to lately. The only guideline we really had was that songs shouldn't be stuff that pretty much everyone already knows; our focus was on discovering new things, things that the playlist creator liked that we'd not have found otherwise. It's great because you feel obligated to listen to the playlist that they made, even if it's not exactly your thing, and it opens you up to a lot of new music. I'd certainly be up for this, either as a swap, or as a album-club-style one playlist a week that we all listen to sort of thing.