In Battlefield 1942, the secret weapons expansion pack. I was playing in the level (can't remember the name) with the snowy lab where the allies get the flying drop point. For those who have never played this, the Allies must capture a Germany Warehouse and the local town as capture points, and it's (in my opinion) one of the best expansion maps in the game. However, the Allies get a plane in the beginning that you or the AI can fly where people spawn inside, then can jump out and parachute down to any point on the map. To counter this, the Germans have (I think) Three AA guns near the lab, that can be used for defense (the AI usually ignores them or uses then on Tanks instead)
Well, I had just eaten a face full of snow (thanks to the tank that had shot me in the back) and decided to choose my spawn point in the air, because jumping out of that plane is, to borrow a phrase, "Totally F*cking Sweet". Anyway, as I selected it and waited to time in, I could have sworn the little "These are you allies" Markers were getting further away from the plane. I then spawned in to fine the plane empty and 4 seconds from the convenient mountainside near the research lab. My "Oh Sh-" was cut off when the plane slammed into the side of the mountain, and I died again.
This, coupled with the fact that my two friends (who were rotating with me for matches) were sitting right behind me, is why I have confidence saying this is my most embarrassing moment ever in gaming history (and I certainly hope ever)