Need a d10 roll? Just look at the last digit of the current second on your clock. Is it random? No, but it approximates randomness if you only make a roll sporadically.
Use hundredths of a second on the stopwatch. With a little math, and throwing out invalid results, you can generate a random number in any range < 100.
Though I do wonder if the hundredths are true or just for show. Maybe they're randomly chosen. :)
It’s pseudorandom. It’s predictable in theory because if you had another watch, or an amazing sense of time, you could predict it. Is that realistic? Not really.
Computers use their clock to generate pseudorandom numbers all the time (hehe). It’s great randomness for something like shuffling songs or a sorting algorithm. You don’t want to use it with some “adversarial”, like online poker.