Some colleagues and I have the new Microsoft Optical Wireless Desktop Pro keyboard and mice packages. They're pretty nice to use as well. However the issue we had was that Gina's (one of my colleagues) keyboard kept interfering with mine. So, things she'd type would come up on my screen and vice versa!!! (another ! to add oomph!)
I just got off the phone with the techie guy from Micrsoft, from a 45 minute call to try and figure out what the hell was going on. He was as gobsmacked as me! We finally figured out how to fix it though, basically we have to spoof it. My PC has to be off if Gina changes batteries in her keyboard so that it doesn't take the frequency mine is on or something like that.
Just wierd thats all. :P