Finding a place to nap in an office an environment can be tricky, but if you start thinking of your nap as an important work tool and not an embarrassing indulgence, you can usually find a way to make it work. Drop a few bucks on a good pillow, blanket, sleep mask, and/or white-noise headphones -- whatever's important for you -- to keep at your desk. (For me, the sleep mask is critical. YMMV.) Get creative with your sleep position -- couches are great, but I've made it work lying on the floor with my feet up on my office chair (suitably chocked so it won't roll away). The key point is, don't be afraid to ask the work environment to adapt to your nap, rather than vice versa.
CAR:
I used to go to my car and take a nap. Kick the seat back, eye cover, maybe ear plugs and put the alarm on vibrate and in my shirt pocket.
Depending on someones situation and their proximity to their vehicle, if they drive.. It could be good.
YOGA MAT:
Everyone likes being hip and yogic. Buy a yoga mat. By tying yoga mats to napping it seems all so, much, more okay.
It's easy to lie on the floor, once you learn to nap on the floor you'll have the most refreshing naps ever.
Some people have a room they can go to, or maybe a spare office / meeting they can use / book.
In general, I've found the biggest obstacles are social (i.e., people think you're lazy), not logistical. But these are largely gone for me now that I'm running my own company. My cofounder and I have vowed to not just tell any future employees that napping is acceptable, but to actually keep doing it, so they see that we're serious and feel comfortable napping themselves should they want to.
I'd recommend telling your coworkers/boss that napping makes you more productive, and that you only take one 20-minute nap a day. If they're silly and care about exact minutes worked, just show up a few minutes early or start a bit later.
Genuinely curious: How much of the sleep deprivation is due to employment practices, and how much is due to, say, American cultural values? Are we sleeping less because our employers or our social lives demand more?
But some are lucky genetic mutants. I am not one of them.
Options here are obviously, book a meeting, pretend you're going for a run, out to lunch or a coffee.
A shameless plug: I wrote a post about how I learned to nap here: http://unschooled.org/2011/05/how-i-nap