SystemUIServer Unresponsive?!?!

I have 15" mid-2010 MBP, 1TB HD, 8GB memory, Core i7 processor, 2.66Ghz. It's about 2 and a half years old. I updated to Mountain Lion about 3 weeks ago.

The last week or so it's been running much slower than usual, and when I check activity monitor to see what is slowing everything down it has been the SystemUIServer--ramping up to 94% CPU.

It has even gone unresponsive multiple times, whereby I cannot even click on the airport, user, spotlight or other Apple menu bar items. How can I fix this?