All,

My BB 8700C vibrates at random hours i.e. 8:59 am, 10:59 am for no reason. I'm not receiving any messages or calls when it vibrates. Any suggestions?

Do you have any calendar items, tasks or other profile settings set to vibrate?

Yes, I've checked to see if there are appointments or other items that would trigger the vibration and there is not. The strange thing is that it happens sporadically.

check your IM programs. With yahoo and ramble my BB vibrates when people sign in or out and there is nothing showing you that it just happened

Do you have any items in your profile that should be triggering vibrate mode?

If so, try creating a non-vibrate profile and see if you still get any vibrates. If not, start adding back one type of vibrate at a time, and that will at least help you narrow down the source of the issue.