This really goes under the heading, “did not really think this one through”. It all started simple enough. A co-worker is having a milestone birthday. Someone suggested filling cube with a bunch of balloons. It sounded like fun. I recruited a co-conspirator and made a plan. First question is how many balloon? If you assume that a typical 12″ balloon occupies a volume of one cubic foot and a typical cube is 8x8x5, then I would need 320 balloons to fill the space. Next step is to find some balloons. Target has bulk balloons but they only had assorted colors. Next stop was Party City with helium quality (read expensive) bulk balloons in a variety of colors. Given the milestone, black was chosen as appropriate. I decided that two bags of 72 would be sufficiently obnoxious. My plan was to inflate the balloons the night before but I was concerned that they would be all deflated by morning. I did one balloon test that was still full four days later. These are good balloons. The prospect of transporting that many filled balloons meant that I would be filling them in situ. Fortunately I have a little portable air compressor with an attachment for air mattresses. My timing showed it takes about a minute to fill one balloon. Additional time is needed to tie the balloon off. My co-conspirator took care of containment and tying balloons but abandoned me after the first hour. I had it down to about 75 seconds per balloon so that math worked out to 3 hours with the little compressor pumping away. At one point, the cleaning staff came by and just shook her head. It all paid off. When the victim came into work this morning he was properly surprised.