Check the NBC TV listings and it lists every sport, every athlete, every everything that's happening at any given time. But you just want to know when Team USA is competing because watching Poland versus Croatia in men's 68kg taekwondo isn't your thing and you don't know what the hell a modern pentathlon is. That's fair. NBC's schedule doesn't make it easy to figure out what's going on.
You laugh, but tracking down every Team USA event is as simple as Googling it, and that's not because the top search result is going to give you what you want. It's because Google's Olympic calendar is the best one out there.