It was a parody of What Ever Happened to Baby Jane? starring Bette Davis and Joan Crawford. It was very well done parody, which was a great fit for the episode since Lisa`s jealousy of Maggie was much like Jane`s jealously of Blanche.
Smart and Smarter (FABF09)
Simon Cowell voices an interviewer for a pre-school that Homer and Marge are trying to get Maggie into - but when she gets in, Lisa doesn't take it particularly well.
Note: This Sunday, the ep will be followed by "I, D'oh-bot", originally aired 1/11.