UBR is a Dilbertism for unfocused boss rambling, the period of time at the beginning of a meeting in which the pointy haired boss rambles on about random stuff, wasting everyone's time.
Having not worked in the business world as yet, I have no idea if this is something that actually occurs in practice. As a member of academia, however, I am horrifyingly aware of the strain that UBR can place upon your time when you really need to get something done and your research advisor wants to talk about anything but something important.