I'm gonna have a cow
A loud way to say you're so mad or excited you're about to start mooing. People might think you're actually keeping cows in your bedroom. If you're dumb enough to believe it, start making cow noises in the middle of class.
I had a cow when my dog peed on my homework.
When I got my first cell phone, I had a cow in the hallway.
When my friend said my crush liked me, I had a cow so loud the teacher gave me a time-out.