In 'The Simpsons', what is Homer's famous exclamation?

What is Ross and Monica's last name in 'Friends'? In 'Friends', what is the name of Chandler's on-and-off girlfriend known for her laugh? In 'Seinfeld', what is George Costanza's fictional company for importing and exporting? In 'The Simpsons', what is Bart's catchphrase? In 'The Simpsons', what are the names of Marge's twin sisters? In 'The Simpsons', what is the name of the family dog? In 'The Simpsons', what is the name of the family cat? What cartoon-within-a-cartoon do Bart and Lisa watch on 'The Simpsons'?