UPDATE: They fixed half of it already!
Club Penguin’s Card-Jitsu Snow and Marvel Superhero Takeover parties may have ended, but you can still access some of the special rooms!
If you want to access the Ninja HQ, login to Club Penguin with this link.
If you want to access the Marvel Superhero Takeover room, login to Club Penguin with this link. (I had tried it last month but it didn’t work, and now it does!)
Enjoy it while it lasts, everyone! I do not know if you’ll get banned if you try to get the items from the catalogue, so do it at your own risk.