Club of people who spot a word just as time runs out.
The game was otherwise unremarkable, until right at the end when I spotted "determinablenesses". Partway through typing, I realized there was an "un" I could have put at the start for more points. I typed as fast as I could to finish, then began typing the better word. I got halfway through when the game ended.
One more thing: I would swear that a thread with this name or a very similar one exists and is still active somewhere. But I looked through all the forum categories and couldn't find it anywhere.