"Yeah, my - time-telling device that attaches to my wrist - would've done it, but that didn't follow me here.  Anything with a precise physical symmetry will do, though, like if it's got two identical sides you can flip it and see which side comes down."

"Totally random question I keep forgetting to ask, how do you tell the time around here?"

"Yeah, my - time-telling device that attaches to my wrist - would've done it, but that didn't follow me here.  Anything with a precise physical symmetry will do, though, like if it's got two identical sides you can toss it upwards while spinning it, and you can both see which side lands facing upward."

"Totally random question I keep forgetting to ask, how do you tell the time around here?"