My wife once discovered me, laying on the floor of the office, mostly under the desk, not visibly moving. She panicked until she figured out that I was screwing the mounting bracket for a switch to the bottom of my desk. Ever since, there's been a hardware moratorium at our house.
Of course, there's been exceptions. She did buy me the Raspberry Pi last December. It's what I've been up to the last few nights, though, that may be ruining that exception or maybe even triggering a Crazy-Eddie-The-Used-Car-Salesman event (i.e., "everything must go!").
In an effort to cut back on the electric bill, I'm moving a number of "core" services off of the desktop computer (which draws 300W 24x7) and placing them on a "slightly modified" GoFlex Home and the RPi. This will lower the power drain by about 90 percent (less than 30W).
The dangerous part: the only place to put them (to be able to use wake-on-LAN to remotely start the house server) is on my wife's desk. Her desk has a hutch, which causes the monitor to hide a bunch of empty space behind it. I took advantage of it being dark back there and positioned the GoFlex in there with the LED facing where it can't be seen.
Earlier this evening, I was looking for an innocuous place to put the RPi. I discovered that her monitor has VESA mounts. Since the other half of her present to me was a VESA-mount case for the RPi, I wonder if she'll notice a couple extra cables (power & Ethernet) running to the back of her monitor. We'll see...