Its Wimpy Kid Gregs birthday and youre invited to the chaos. In Partypooper, the 20th book in Jeff Kinneys global smash-hit Diary of a Wimpy Kid series, Greg Heffley is planning the ultimate party for himself. But when the guest list grows, the decorations flop, and the surprises backfire, this birthday bash turns into a total blowoutjust not the kind Greg had in mind.