A new Party mode where you would be able to open a mini-ranked, choose the map and format (time limit, rounds, mode, health, multis, 1v1/2v2/3v3..., etc) and people would be able to join it and play it like ranked - there would be a mini ELO leaderboard for the participants and they would match with someone random in the mini-ranked queue. The host could keep it open until he wants and when he wants to close it, he could click the button and the final leaderboard would show up proclaiming the winner, 2nd & 3rd place, etc. This would be great for streamers, for community events and just fun in general.