A couple of years ago I asked Twitter for education-themed Halloween ideas, and this year a bunch of good ones finally appeared (many of them thanks to @chadadelman):
Dress up as the letter "J." You are Pre-K.
Constantly hold a marshmallow out in front of you. Don't eat it. You are Grit.
Go to Halloween party. Interrupt long conversations. Upend punch bowl. You are disruptive.
You and a friend buy a bunch of apples, put holes in them, then glue them all over your bodies. You're the Common Core
You and friend dress as lemons. Start dancing. You are forced placement.
A group dresses up in running shorts, headbands and runs on an incline? RTT
Think you can do better? You know what to do #educostumes idea? #educostumes or #eduhalloween
From 2011:" Got any last minute ideas for new Halloween edu-costume? Scary Michelle Rhee and Not Waiting For Superman are so 2010."