Today, of course, is Aprils Fools' Day. This office prank actually happened last week, it was close enough in time to qualify...
My friend and colleague Chris came back from his extended vacation (aka sabbatical) to find his office had been appropriated by the shipping department for a packing peanuts storage facility:
I have nothing but admiration for the intrepid perpetrators of this most excellent office prank. The photo above hardly does it justice. DIY instructions and more photos on Instructables. Since then it has been slowly making its way across the internets. It made today's Popular Mechanics Top 5 April Fools' Day Office Pranks list, as well as #7 on LifeHacker's Top 10 Harmless Geek Pranks.
Update: OMG, Chris' office made today's NPR Talk of the Nation! Rock star territory! :-)