I've played with this a little bit over the last couple days and am completely blown away by the ease of use. If you're remotely interested in styling your own

I've played with this a little bit over the last couple days and am completely blown away by the ease of use. If you're remotely interested in styling your own maps (particularly for a mobile app), you should try this out. It exports to an sqlite-based tile store that you can use to display your map tiles while away from a network connection.