Not my most embarrassing, but the most recent!
There was a horse show at my parents this weekend and some issues came up with the sound system. For some reason, nothing would come out. My brother had gone to check the speakers, while some of us were sitting around the secretaries booth. My Mom asked one of the women if she needed to leave for coffee, or a bathroom break or anything. I said "K's fine, I brought her a coffee awhile ago, the cup is now empty, she can pee in that!"
My brother came around the corner hardly breathing. Speakers were fine, and I had just spoken to about 200 people over 100 acres