Never resign!

The diagrammed position occurred in an Australian Junior Championship a number of years ago. It is black to move and clearly White is lost, and had been for some moves. However, White chose to play on and was rewarded with 69. ... c3?? when after 70.Rg6! Black played a few more moves before agreeing to a draw (as White either checks forever with the rook, or is stalemated if Black takes it off the board).
That half point turned out to be quite significant as the player with the White pieces tied for first in the event and then won the playoff to become Australian Under 12 Champion. I'll leave it as a small puzzle as to who it was, but since that event they have had (and continue to have) a very succesful chess career.