Has an AFL game ever ended 121-79?
Exactly once. On August 20, 2010, Geelong beat Carlton 121-79, and no AFL game before or since has ended that way. When it happened it was a scorigami, the first 121-79 in league history.
That makes 121-79 the 3836th most common final score out of 6,607 that have ever occurred in AFL. One point away, 122-79 has happened 1 times and 121-80 has happened 4 times.