Here's the man himself at the Halo 3 launch party. We were playing and I turned around randomly when he entered. There weren't many people flanking him at that time... I thought to myself, "He looks like... no wait. That is Bill Gates!"
And I was glad that I snuck my camera in. It's not a great photo by any means and I could have cropped it a bit... but I just wanted to upload it.
I also took a couple more photos but then I realised I was in the middle of a game so I needed to sit my arse back down and kill some red team members.