Unless your house looks like the grid from Tron, your wireless routers and repeaters probably look pretty ugly and out of place. DIYer Bradley has a guide to hiding your repeater's circuitry in something a little bit more attractive.
OK, I might be using the word "attractive" loosely, considering he hid it in an old 1980s radio — hardly the pinnacle of beautiful technology — but the principles from this project can apply to nearly anything you might want to hide it in. What's really cool is that in his example you don't even need to break the radio to put it all together — it's still completely functional after the process is complete. You'll need a bit of soldering expertise, not to mention some familiarity with whatever you're hiding the router in, but if you have any experience with electronics it should be a breeze. Hit the link for the full how-to.