With Google Now, you can say "Navigate to Home" and it knows where that is. Now, Google has added the ability to use that same feature for your hotel, if you have an itinerary in your email.
The feature works basically the same way it does for the Home or Work addresses. If Google detects a hotel address in your email, it can add that to the list of places you can quickly identify with a voice command. It's not just directions either; you can ask "show me restaurants around my hotel", and Google will let you know what to eat nearby. It's not clear how widespread this option, but it's worth checking if you're travelling.