What the heck is that beeping???

So, 3 days ago a very high pitched soft beeping started somewhere in the kitchen region of my house.  It has graced our presence since and hasn't stopped.  Its melodious sound beeps every 5 - 8 minutes or so.  We have looked everywhere for its source and can't find it.  And before you say it.....it isn't a smoke detector, watch, cell phone, ear thermometer, back up ear thermometer (because 1 just wasn't enough), DS, dog anti-bark collar or regular house phone.  How do I know???  Because all of those are in my kitchen and I have walked around with them one at a time in my hand till I hear the beeping to see if any of them are it!  I have looked under things, over things, around things, between things, beside things and the source remains a secret.  Hold on a minute.....it just beeped again!  My husband and kids and I will be in the kitchen or family room (which is connected to the kitchen) and we could be talking or watching t.v when suddenly the beeping happens.  We all kind of freeze as our eyes roll around in all directions looking as if the beeping is actually going to attack.  We are stumped and can't solve this mystery.  As the days roll on I am more doubtful that I will.  I have designated the beeping as a "time to take my pills" alarm.  I don't necessarily have any pills to take....(although, I have been known to take them), but if this beeping is going to be a permanent part of our lives I wanted it to feel useful.  So it is the official "time to take my pills" beep.  Just beeped again!!!  Hold on, let me take my pills!  I wonder how long I can last with it.  My friend came over today and was driven crazy after 1/2 hour.     Just beeped again!  Wow, that one was only 3 minutes.  I think it's playing games with me.  I'll keep you posted if I find anything out.  OIT  *BEEEEEEEP*