This isn't about the wonderful Central Casting products from the nineties, though I got quite a bit of use out of them back in the day.
This is about how Casting can improve your game. Now, first off, this doesn't apply to games where you're playing giant robots or mutant chickenmen or a very non-human character.
When I refer to casting I refer to asking the player, prior to play, who would play their character in the movie that is the game session.
I've been doing this for years and it really helps some players visualize their character better. It also helps the other players see the characters around the table as not just the player with a character sheet.
I realize that not everyone out there will have an encyclopedic knowledge of cinema and its not required. IMDB is your friend but, as always, talk to your players, ask questions, get feedback and don't force your idea on them.
As always, tailor to fit your group. If someone is resistant to the idea, don't force them.