I think it was... aww nuts, now I'm going to have to build the stupid thing. Wait right there, brb -
...
Here you go. Answer is: depends on how you press it. Press it slowly at the right rate and it stays on for almost a second. Tap it and you get a blink. Dropping a coin maybe an inch onto it also gets a good flash out of it. The "button" is a piezo disc, bigger ones work better.
See how I got that diode hooked up, prprog? The piezo is like a piston in a pump, sorta. The diode and the base-emitter junction act like two valves in the pump.