The Simpsons' Treehouse of Horror #22
First of all, Bongo invites everyone to visit the Retirement Castle of the Vampires! Really... even your older, bloodsucking relatives need some attention. (Visiting hours are from 9 to 6.) Then, former couple Lisa and Nelson team-up to investigate paranormal activity at Springfield Elementary, prompting them to open The Ex-Files! And something's really strange in the neighborhood when the Ghost Bashers come to town!