I found this idea here, and basically, all that you do is get a 3D letter or shape (I think that a heart would be really cute!), and cover it in a road map. You simply need to trace around a road map, maybe of your favourite place?, cut it out and glue it onto the 3D shape. And you can even put little toy cars on it, kinda like they're driving!
Let me know if you try this- it just looks super cool!