Nothing.
I keep a Linksys WAP11 in the closet upstairs for mobile and guest connectivity. Pinged it from the desktop, no response. The power lights were still on, so WTF? I figured maybe it got goofed up in the power outage a while ago, so I held the reset button down to get it into default config. ifconfig'ed up the 192.168.1.x network the Linksys jumps on by default, and pointed a browser at it.
"Firmware Upgrade"???
Well that would explain things, it's somehow shit its firmware. Let's give that a whirl. Download from Linksys, point the browser at it.
"Firmware Upgrade". Same thing. Okay, reset it.
The lights go into an odd little pattern. Not the usual blink, blink, blink, spur of activity as it boots. Power, activity, link, then just power. 1, 12, 123, 1, 12, 123, about a second apart. Kinda looks like it's in a reboot loop. I spend an hour searching the net, I find Eric Raymond's Blue Box Router HOWTO, which has a reference to "dirty power". Well that would explain things... the box starts booting up, starts up enough components to increase the current draw to a point the wall wart can't keep up anymore, and the voltage drop causes a reboot. Lather, rinse, repeat. I crack it open and jumper in a 6v supply I keep around for testing. Sho 'nuff, the WAP11 comes up in its normal configuration, says 'hi' to my iBook, and away it goes.
Fortunately, Laptops For Less sells replacement wall warts for these. $15 is a little pricey, but try finding a 5VDC 2A wall wart. Things to keep in mind the next time one of these goes flaky on you. (I have one deployed at the high school, and I'm planning on setting up three more to bridge me a network out to my press boxes.)
On a side note, LFL is also selling a small mouse-sized GPS receiver (the Globalsat BU303) with a USB interface. It looks interesting, and I found there's an OS X (and an OS 8/9 as well) driver available for the Prolific USB-serial bridge chip used inside it. You have to walk through the Downloads section of Prolific's web site, it's the PL2303 under USB 1.1 full-speed cable controllers. The receiver spits out standard NMEA sentances (unlike newer Garmin models,) so it should work with any good mapping software. I'm going to take a look at it.