Complex sentence: When on the phone, Penny mentions "the only time (she'll) be cast as Anne Frank"; the character played by Kaley Cuoco on "8 Simple Rules" was cast as Anne Frank.
Split into simpler sentences: When on the Phone, Penny mentions "the only time (she'll) be cast as Anne Frank". The character played by Kaley Cuoco on 8 Simple Rules was cast as Anne Frank.