In the (awesome) video above, Schafer takes on the role of interviewer, talking with Gilbert about their shared history in adventure game-making, playing, and learning how people play adventure games.
They cover territory from Monkey Island through Psychonauts, and Gilbert has some killer quotes about how adventure gaming never died, it's just that other games became more popular, as well as why he doesn't consider L.A. Noire or Limbo to be adventure games.
They cover a ton of other ground, and there's so much good stuff in here that I couldn't hope to recap it. Just sit back and watch, and enjoy. And, if you're strapped for time, the folks at 2PlayerProductions have edited together a 5-minute highlight reel.