The Medieval Party may be over but you can still go to the Tree Forts and first Knight’s Quest!
To log in to the Tree Forts, use this link: http://play.clubpenguin.com/?rm=851#login/
To log in to the first Knight’s Quest, use this link: http://play.clubpenguin.com/?rm=852#login/
Update: Here are more, as supplied by Phineas99:
Second room for the first Knight’s Quest:
Bridge of Destiny:
Mountain of Misery: