The Chalk Closet was the first short story in the book, Even More Tales to Give You Goosebumps.
Travis goes to summer school. The teacher, Mr. Grimsley, explains to the class that if anyone does not do their homework, they will be put in the Chalk Closet. After being given homework, Travis does not worry very much but does part of it. But his acquaintance, Dooley doesn't do it at all, and the next day he is sent to the chalk closet. No one ever hears from him again and everyone just assumes that he was kicked out of summer school. The next day it happens to Marty, and soon to Janice.
Soon after, Mr. Grimsley announces that there will be a test and that everyone will have to get an A on it. Travis is the only one in the class who doesn't, so the teacher takes him to the Chalk Closet, opens the doors, and slams it shut behind him. He turns to see all the missing kids and hundreds more in the room with their hands over the ears. Then he hears the noise of chalk screeching across the board and realizes he'll spend eternity the same exact way.