So many people decide to spend the night at Winterfell during the events of A Clash of Kings. It can be hard to keep track of them all, but we've got the handy-dandy guide to this slumber party:
Luwin is the maester that serves Winterfell and House Stark. He advises Bran, helping his young lord manage the difficult task of ruling the North. He also serves as a surrogate parent for the young Starks. This is especially true for Bran, as the maester tries to help the boy learn to accept the reality of his paralysis (17.Bran.41). In fact, he kind of acts like a surrogate father for everyone at Winterfell, even scolding the Frey boys for poking fun at Hodor (17.Bran.35).
Finally, Maester Luwin follows his duty and serves the realm. Even after Theon supposedly kills Bran and Rickon, Luwin still advises him to take the black and join the Night's Watch (67.Theon.89). Luwin is mortally wounded during Ramsay Snow's destruction of Winterfell.
Ser Rodrik is a loyal, dutiful bannerman of the Stark family. He also advises Bran with Luwin. He helps fight off the Ironmen who assault Torrhen's Square, and returns to reclaim Winterfell from Theon Greyjoy. He is killed by Ramsay Snow, when he is pretending to join Rodrik's cause before figuratively stabbing him in the back. Ramsay literally cuts off the man's arm.
Hodor is a giant of a man who carries Bran around the castle and to the godswood. Although he has hands strong enough to take a man's head off, he has a gentle, passive personality (17.Bran.97-98). He suffers from expressive aphasia and so can only say his own name. He joins Bran on his journey north.
Although Osha was taken captive as a wildling, she has since become devoted to the Starks, especially Bran. She offers him advice about his dreams and discusses the old gods with him (5.Bran.79). She appears to swear fealty to Theon, but later helps the two Starks, Meera, and Jojen hide in the Winterfell crypts. She agrees to take care of Rickon when the group separates at the novel's end.
Meera and Jojen Reed were sent to Winterfell by their father to pledge their house's loyalty to the Starks during the harvest festival. Jojen has the gift of green dreams, which allows him to see into the future, although the truth of these dreams can be hard to decipher (36.Bran.28). Jojen's goal is to help Bran unlock his potential and open his third-eye. As he tells Bran, "A knight is what you want. A warg is what you are. You can't change that, Bran, you can't deny it or push it away" (36.Bran.52). Both Jojen and Meera accompany Bran north at the novel's end.
These boys are members of the Frey family who are staying at Winterfell as the Starks' wards. Both are named Walder Frey after their grandfather, so they are distinguished by their vertical accomplishments (5.Bran.55). The Freys are both cruel and self-centered children, making fun of Hodor for being simple and acting as Bran's horse—only Big Walder looks "abash" (Bran.17.33) when scolded by Maester Luwin for their actions. Little Walder also joins Theon's hunt for the Stark brothers later in the novel.
Lady Donella Hornwood is a vassal to House Stark. Her husband died fighting for Robb in the south, and Ramsay Snow kidnaps her and forces her to marry him so that he might claim her lands. Ser Rodrik attempts to rescue her, but when his men find her, she is already dead. Ramsay locked her in a tower and starved her, and she chews her fingers off to sate the hunger before meeting her end (36.Bran.63).