I was doing a little lesson on time yesterday. First, I we went through some pronunciation stuff, in particular differentiating between "thirteen" and "thirty" and the like. Then we played a game where I called out a time and the students had to draw it on a clock on their little mini-white boards (which are, by the way, absolutely the most revolutionary teaching tool I've found for increasing student participation, understanding, and retention). I would tease students (cheerfully) if they drew, for example, 2:50 rather than 2:15, and their teammates would heckle them until they corrected it. Lotsa chuckles.
Then I started working on alternate ways of saying the times. I wrote on the board, "5:00," asked "What time is it?" and got them to say both "It's five o'clock" and just "It's five." Then I drew up "5:15" and elicited "five fifteen" and, after a bit of work, "quarter past five." Next, as you might expect, was "5:30." "Five thirty," most of them say. Then one wiseass, with a big grin on his face:
"Two quarters past five."
Maybe you had to be there? Anyway, it was awesome. Sometimes I love my job.