Flash game: Socrates Jones: Pro Philosopher. The gameplay is similar to Phoenix Wright: Ace Attorney, but you instead debate famous philosophers in an attempt to understand morality.

It's pretty short and suffers from the "I know the correct answer here, but how did the author of the game intend me to indicate that" problem, but I found it fun and interesting nonetheless. It helps to keep the walkthrough at hand, so you can resort to it if you start getting frustrated. Even though the arguments were only addressed relatively briefly, I actually felt like I'd learned something. Liked the music, too.