My weirdest experience was the time my Xoom would not turn on nor respond in any way. It had been working normally, and I had let it go into it's normal "screen off" mode, and had let it sit fro about half an hour while I was busy with other things.
When I tried to "awaken" it, it was unresponsive. It wouldn't even reboot with an extended depression of the rear button.
I considered that it might have run out of power (odd, since it had been showing near full charge when last in use), so I tried hooking it up to the plug-in charger. The charging indicator light did not even turn on. I then considered that the mobile charger I was using might the defective, so I placed the Xoom on it's dock (with the charging contacts) - same result.
At that point I feared that a physical problem had developed with the unit, perhaps in the power distribution seeing as how it wasn't even charging.
I took it to the Verizon store where I had purchased it, where it was put through a battery of tests and procedures, to no avail. The Verizon rep arranged for Motorola service, and for a shipping box to be sent to me.
That evening, I went on this and another (Motorola Xoom) forum to whine about my dead Xoom. The typical "volume down/power button" factory reset combo was suggested (which had repeated tried at the Verizon store), the another poster suggested the "volume up/power button" combo (which the manual suggests for "freeze ups".
It tried it three time before it worked for me. The first couple of times, I held the buttons for 6-10 seconds, that last time (mostly due to frustration) I held them for a quite long period of time (it might have been close to 20 seconds), and the thing finally began the boot-up process.
I have never had this happen since, and everything seems to be working correctly - even the apps that I recall having had running prior to it "dying" (well, it wasn't really dead, more like a deep coma).
After my noting this experience on this forum, several other owners reported similar experiences that they had encountered. I don't know if it's a hardware flaw, of perhaps a flaw in 3.0 that will be resolved in subsequent releases. Either way, I'm just glad it hasn't happen again since, glad to know an easy "fix" if it does, and glad to be able to share that fix with other owners who may experience the same issue.