As misfit Jerri Blank, Sedaris is obnoxious looking and lacks the comic sills to turn unpleasantness into hilarity. Jerry Lewis playing oddball characters comes to mind. When doing his best work he could be very funny with his body movements, timing and coping with uproarious situations. Sedaris’ Blank is merely off-putting.

The dumb plot itself would be enough of an obstacle for anyone. “Strangers With Candy,” directed by Paul Dinello, was written by, in addition to its star, Stephen Colbert and Dinello. What they came up with is a situation in which Jerri, 47 years old and fresh out of a long prison term after a wretched life of boozing, drugs and what not, comes home to find her mother dead, daddy in a coma and Deborah Rush, dad’s new wife, looking disdainfully upon her. Jerri thinks she can awaken her pa if she does something sensational. Hence, she enrolls in high school to catch up on her education and make something of herself.

There she is a total misfit amid the nasty girls, a boy who heaps unwanted attention on her and a jock whose attention she craves. Colbert plays her science teacher in a performance more outrageous than funny. Gegory Hollimon portrays a shifty principal and there is a to-do about how to win a science fair amid assorted intrigues. Lending some misused casting prestige to this hapless enterprise in assorted supporting roles are Matthew Broderick, Sarah Jessica Parker, Philip Seymour Hoffman, Allison Janney, Dan Hedaya and Ian Holm.