Setting:  My office
Time: Within the last few days
Characters: Me, my interns T & H
Activity: Me – answering e-mails; T & H scrapbooking

T:  What part of speech is the word crazy in the sentence, “She is crazy.”
Me:  Well, my first thought is adjective, but that’s not right.
T: It’s an adjective being used as a noun?
Me:  Yeah . . . that happens all the time.  It’s a predicate nominative.
H: The sentence has a linking verb, so crazy has to be a predicate nominative.
T: Predicate nominative . . . that makes total sense.

Everyone resumes previous activities.

photo courtesy of nullalux and this seems to be the original source.