Can I buy a soundproof box to stick my server in?
jsz0: Have you considered buying a silent computer? I think it would be cheaper than an enclosure. Depends what type of power you need though. Mac Mini is good for this or maybe ATOM if you can get by with it. An easy solution I've used before is to stack a small wall of books in front of a loud device. Don't fully enclose it just make a little wall between yourself and the laptop. It may not erase the sound entirely but it will definitely smooth out the higher frequencies.