Who is the biggest band or artist you've seen perform to the smallest audience?

I saw NYHC band Subzero at a dive bar in upstate New York around 2009. Other than the bartender, I was literally the only other person there that they didn't bring with them. Even the opening bands left by the time they went on.

For big venues, the first Gigantour. Megadeth, Dream Theater, Fear Factory, Dillinger Escape Plan, Nevermore, Life Of Agony & more. Maybe a couple hundred people there in a huge amphitheater. Paid for lawn tickets. It was so empty, security said we could sit wherever.

Oh, I also saw the Foo Fighters play in the basement of an HMV for the secret cd release show of There Is Nothing Left To Lose. Maybe 50 people there. I was 14 at the time and had to stand on a bunch of shopping baskets in one of the aisles to see.