doobie doo
An expression that can be used for emphasis after an exclamation.

OR

When used with a rising pitch at the end, it can be used to ask a question

OR

Can be used to refer to marijuana

Origin:

This phrase originates from an impersonation that was done of Bill Cosby.  In it, the joker would say 'Doobie doo, Theo eat some pudding pops' after smoking a joint.  

Eventually, this evolved and "Doobie doo" became a phrase of its own. 
I've won twenty dollars off that idiot because he bet me Dustin Hoffman was in Star Wars!  Doobie Doo! 

I missed Battlestar Galactica, but it's on again at 10.  Doobie doo! 

OR:  Doobie Doo?  Is Jessica Alba really naked in that movie?

OR: Hey man, I've got some friends coming over, can you get me some doobie doo? 