[Judd Hirsch in "Knock Knock".]

[Jules Feiffer and the cast of "Knock Knock".]

[Jules Feiffer and the cast of "Knock Knock".]

["Knock Knock" theater still.]

["Knock Knock" theater still.]

[Leonard Frey in "Knock Knock".]

[Leonard Frey in "Knock Knock".]

[Leonard Frey in "Knock Knock".]

[Neil Flanagan as Abe in "Knock Knock".]

[John Heffernan as Abe in "Knock Knock".]

["Knock Knock" theater still.]

[Leonard Frey in "Knock Knock".]

[Charles Durning as Cohn in "Knock Knock".]

[Neil Flanagan as Abe in "Knock Knock".]

["Knock Knock" theater still.]

["Knock Knock" theater still.]

[Daniel Seltzer as Cohn in "Knock Knock".]

[Neil Flanagan as Abe in "Knock Knock".]

["Knock Knock" theater still.]

[Judd Hirsch as Nat and Cleavon Little as Midge in "I'm Not Rappaport".]