I have no ideas today, so we're going to take something and I'll riff on it, and see if we can produce one or more adventure seeds that way. This might be a bountiful harvest of ideas or it might be awful; if I edit this, it will be for presentation or spelling, not for content.
American Thanksgiving is coming up, but my (Canadian) Thanksgiving was last month. So, being between Thanksgivings, I'll take that as my theme.
Thanksgiving is traditionally a time of family togetherness. What if some big bad villain escaped from detention but it's actually so that he or she can spend the holidays with the family? Maybe Dad is dying or something, and this might well be the last Thanksgiving they spend together. The villain can't get out without the help of some others, so there's a whole group there (some of whom don't care about the holiday, so they're happy to loot or whatever, and when caught, they point the finger at Villain's family house. It might look like this:
The PCs are looking forward to their own festivities when the Midnight Throne escapes from his maximum security prison, with the help of several supervillain associates (past villains from your campaign or perhaps Dark Silver, Chicle, Solar Flare, and Limpet, to invent some names). Limpet and Chicle are easy enough to catch because they're busy hijacking a teleporter to get out of the nation, and they eventually point to a quiet suburban home, where the Midnight Throne is having Thanksgiving dinner with his two associates and his family. The ensuing fight puts Throne's father in the hospital--will the PCs let Throne go there to say goodbye?
Mind, there might be some juice to be gotten from avoiding a family get-together as well.
Lots of the team is off enjoying Thanksgiving but several people have volunteered to be on watch duty. They don't actually want to go home. The problem is that even the crooks seem to have taken today off. The PCs respond to an environmental emergency, and that's good, but there's still nothing. Else. To do. They're about to break out the D&D books (and really, don't you want to roleplay your heroes roleplaying D&D?) when the alarms go off. Someone is inside the base!
Now, it could be a story where their companions have decided to bring them some turkey and pie, or even one where the villains bring the food, but in the tradition of Kitty Pryde's Christmas, I'd rather it were other-dimensional invaders. The bad news is, there are a lot of mooks. The good news is, the interdimensional gateway has opened in the hallway on the same for as the Disaster Dungeon, where the team does its training. If they can't beat the invading force directly, maybe the Disaster Dungeon can do it (once they disable the safeties).
And I'm out of lunchtime, so there you go.