It’s definitely one of [Law and Order‘s] little pleasures to discover in just about every episode one of those people you know wasn’t a big deal at the time, but is at least a moderately big deal now. As a matter of fact, you can get to the point where, if you see an important role being played by someone you haven’t ever seen in anything else, you find yourself saying, “Huh. Wonder what ever happened to that guy.”
Methinks there needs to be a snappy name for the “recognizing people who weren’t recognizable when the movie/episode was made but are now” game. It’s right up there with “Hey, it’s that guy!” for good times whilst watching retro movies/TV shows.