the movie was about a man who cheated on his wife. the woman he was cheating with did not know that he had a family, and i think she played some type of instrument (piano or cello or something). The wife shows up while the lady is practicing and confronts her about it and shows her a picture of their nine year old daughter. The lady is in shock so both her and the wife play tricks and schemes on the husband. I remember one of the schemes was wearing a Darth Vader (or something?) mask and prank calling him. Another scheme involved zoo animals in the house.