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3.
When someone says something so outrageous and unbelievable, one may say "Are you out of your tree?" which means that the person is out of their mind on such an idea. The phrase originates from the popular Nintendo game, Animal Crossing.
Tanner: So what are you trying to do here?

Reil: I'm going to jump that shark tank on this here bike.

Tanner: Oh no, no, no! Are you out of your tree?! You can't hope to jump something like that on that thing. You may as well start jumping turtles before doing something so unbelievable.

Reil: But I jumped the turtles last week...
by Tanor-Faux April 03, 2012
 
1.
To be crazy, to do something insane/crazy,
Like being out of your mind
Bob: I'm going to go jump off that bridge

Frank: You must be out of your tree!
by swim4life July 31, 2009
 
2.
1. Pissed as a fucking cunt.
2. Crazy, mental, weird.
1. "You were so outta yo' tree last night that yo' waz starting fights and shit."
2. "Man your'e outta yo' tree, get off tha fucking goey mate."
by Diego September 11, 2003