I've had my Droid for two weeks tomorrow, and today was the first time I've seen this odd behavior.
With the phone on standby, and over 90% charge (I have the battery widget), I came back to it about five hours later to find it claiming it was at less than 5% power and I should plug it in immediately!
I didn't have my charger with me at work, so I turned it off to save that remaining 5%. Plugged it in as soon as I got home, and after it booted, it said it was at full charge. Huh?
Anyone seen this one before?