Today I got to experience something for the first time that would've scared the shit out of me if I hadn't already been briefed on how to handle it (and knew that it was a possibility). I was out flying aerobatics (2nd time solo) and had done most of the maneuvers I wanted to practice. Decided to finish the session with a spin, so I climbed to my maximum cleared altitude, pulled the throttle to idle, waited for stall speed and entered the spin.
And then the propeller stopped turning.
Cue swift recovery from the spin, initiate pull-out, open throttle slightly and push the starter button. Engine came back to life immediately. Phew.
After landing, I made a phone call to the chief aerobatics instructor and debriefed the incident quickly. He told me that it can happen, and in some older aircraft like e.g. the Tiger Moth, it is more or less to be expected. Hence all aerobatics pilots should be familiar with the procedure for restart in flight. Which I was.