Ron, just after kissing Hermione and with the Sword of Gryffindor in hand, yelling "LET'S GO KILL VOLDEMORT!"
A Very Potter Sequel
The introduction to "No Way."
Harry: For 11 years I was a little douche bag locked up under some stairs. But this year? I found out I'm a wizard, and I'm famous. I can fly and turn invisible, and I just traveled the FUCK back in time! So fuck you Draco, how's that for a happy thought?
Lupin's introduction saving Harry from a Death Eater. "Take that, you bastard ass!"
All of the opening scene. "It's Not Over Yet" continues the grand tradition of Villain Songs being the best. In particular the moment when he pulls out the time turner; just listen to the pop from the audience as they realize what the sequel's story is going to be.
Hermione whips out the jellylegs jinx again, this time on Lucius as he's stealing Harry's Firebolt.