Like the one that happened a couple of weeks ago. You were running around the lake you grew up near, the one that, despite all your curmudgeonly seen-it-all-isms, you never get bored with. The bugs were out, you'd almost swallowed a bee, and for one of the only times in your training, you were not craving the miles. You just wanted to get it over with before the bugs got any thicker.
Then you looked up to notice that the combination of the setting sun and rising moon was bathing the lake in an otherworldly orange. Out of nowhere, thousands of seagulls were leisurely flying in from all parts of the city, heeding the same silent call, landing in the middle of the lake. It was straight out of the rapture, or the apocalypse, or the great big secret bird bash at dusk that only you were invited to.
You had never seen anything like it before. You came out of your runner's shell and said to a few walkers, "Look at that! Look at that!" They shrugged. You didn't. You were awestruck, again. You kept looking at the birds, kept running, and almost tripped.