Was really excited to see so many replies... then realized everyone was just confused about terminology.
If you are playing a Hero or Villain, you can click "LFG" on your chat window and see several things you can queue for. Under the "Holiday" tab is the Summer Blockbuster Double Feature. If you haven't tried it yet, I recommend it. You can either queue just as yourself and the game will throw 4 of you from the queue into the trial, or you can join with up to 4 teammates. Nice rewards.
I think most people will start a character as a Hero ("blue"), and some will start as a Villain ("red"). You do have the option to start in "Going Rogue" ("Gold" or "Yellow" or "Maize" or whatever) where you spend your first part of the game in Praetoria. It's not very populated with other players.
I'm asking that, especially given the lower player population in Praetoria, could we perhaps maybe please be allowed to queue for the Holiday trial in LFG. The others would be nice, too, but I'm just asking about this one right now.
Hopefully the next 7 comments can, I don't know, maybe get some discussion going on whether this would be something the community would want, now that we all understand what the terms mean.