Ron plays with a powerful magic device he probably shouldn't have.  One is left with the horrible feeling now that war settles nothing; that to win a war is as disastrous as to lose one.

The group determins that they are in an alternate reality and break into the ministry to make new identities.  
When you have eliminated the impossible, whatever remains, however improbable, must be the truth.

"You can't build a reputation on what you're going to do."The group is interviewed by McGonagall, they share their odd future ambitions, Hermione buys out Florish & Bolts, George gets some bathrobes, and Draco decorates.

“I have five rules. Memorize them. Rule number one, don't bother sucking up. I already hate you, that's not going to change.”  The first classes: George makes people jump, Draco's hates his students, Harry has siblings, and the universe is crumbeling. 

I’ve never taught before, but I’ve been doing this stuff for eighteen years, and I’m still breathing, so that means I know what I’m talking about.  This is not going to be like your other classes.

Cally Potter attacks a teacher, Neville sings, and Harry uses the Elder’s Wand.