1) Networking (wired or wireless) away from the noisy units (not just putting the case in a desk or cabinet).
2) Air-In & Air-Out to the noisy units being piped in/ out via ducts
3) Putting the noisy unit "out-of-the-way". This could be under the desk/ bed, in a wardrobe/ cabinet/ cupboard.
4) Using a noise-canceling audio-generator - an amplified version of the electronic noise-canceling headphone units.
http://telecommuting.about.com/cs/equip ... earbud.htm
http://www.enjoythemusic.com/magazine/e ... phones.htm
http://www.discount-electronic.com/maxell.html
http://www.applesound.co.uk/sales/senn/noisegrd.htm
5) Play music, television; being near crowds/ traffic, kitchens.
6) Use earplugs/ noise-lockout headphones
7) Become emotional involved ... brainwash yourself into urgency (time, deadlines, etc) or extreme emotion (anger, obsession, ...).
.... any more ... ?