Dream on Dennis Quaid 

Used to shoot down someone's thoughts, actions, or feelings in a witty and formal way.

It is a reference to the move, Dreamscape, where Dennis Quaid plays the main role. He enters people's dreams and helps them conquer their fears.

Person A: "I've been wanting to ask you this for a long time...will you marry me?"

Person B: "Dream on Dennis Quaid"

Dream on Dennis Quaid by Mr. Councilman April 25, 2011

Dream on Dennis Quaid 

The alternative to the overused "ohp nevermind" which has more class and wit. Used when someone says something that the speaker wishes to reject or shoot down.

Person A: "Did you just see that badass backflip I just pulled off? It was amazing!."

Person B: "Dream on Dennis Quaid"

Dream on Dennis Quaid by Mr. Councilman April 25, 2011