So I decided to make my web based garage door opener more permanent and safe by putting it in an enclosure. I went to Fry's (an electronics store near me) and they had project boxes starting at $15+ for a simple, thin plastic box. I decided to skip that and went to Home Depot and bought a junction box made of sturdy plastic and was mountable.
The first thing I did was figure out how I was going to lay out the two boards that I had: Ardunio and Relays:
Then I drilled holes for the USB port (for power), the Ethernet port, and for the screwdown terminals for connections to the relays. Originally I just drilled one hole for one relay, but later I drilled a few more.
I drilled holes in the bottom to match the wholes in the board and then screwed the boards down:
I then mounted the box above my garage door opener and ran the appropriate wires.
I am going to buy a Dremel drill for my future projects to make the holes look a little nicer. I also really like this junction box and will probably use it for future home automation projects, at least for the type of stuff that isn't a user-input device.
There are a few more pictures here