My first thought was that the balloons are fake and the desk is attached a strut that is bolted to the ceiling. But no: those are real, helium/hydrogen-filled balloons. This reception desk at the Dublin-based ad agency Boys and Girls is held aloft by balloons that are made to remain permanently inflated. The other end of the table is propped up on giant Jenga blocks.

Link -via Swiss Miss | Photo: Boys and Girls

UPDATE 6/5/12: Two commenters provide good reasons to think that the balloons really are fake.