Awkward incident in which a peer or colleague confuses a local institution or landmark with a distal one. Hilarity often ensues.
Christina: Hillsdale High is very ghetto. It's only 1% Asian.
Me: ...You're looking at the wrong one. We're in CA, not MI. Good job pulling a hillgate.
Retaliatory reply to a social gaffe committed when an individual, usually someone you hold in high esteem, mistakes your work as something puerile or less significant.