A Research Project on Pronouns as Predicate Nouns
Give each student in the class five copies of one of the "Choose" exercises (# 7b in Level 1.6) without the instructions for identifying the constructions. Have each student ask five different people to circle the pronoun that they would use. (You might want to include space at the end for "Comments.") Then have the class count how many people gave each answer for each question. The class can then discuss the results in terms of "formal" vs. "popular" grammar.
To make the results more interesting you can include at the top of each sheet a request for information about age (10-20, 21-30, etc). sex ("m" or "f"), educational level (high school grad, years of college,) and or degree (B.S., M.A., Ph.D.). It would be particularly interesting to see how people with degrees in English respond.