Hoard is an indie game for Windows and OS X that turns traditional fantasy games on their head. In Hoard, you play a dragon, and it's your job to fight off knights, pillage villages, steal gold and gems from travelers, and protect your hoard from would-be thieves.
Hoard is a casual game, but it has a lot going for it that more hardcore gamers would appreciate. It plays like a cross being a real-time strategy game and a board game, without the turn-based play common with angled top-down views.
You can play it solo, or compete with AI and/or real people to build the largest horde possible in a limited amount of time. You have to constantly fend off thieves and pesky knights that attempt to infiltrate your hoard. You can kidnap princesses, raise villages, and even burn fields in order to take valuables back to your stash.
It's fun, addicting, and worth picking up if you want a game that lets you play the bad guy in 15 minutes or less.