Not so much a blooper as just a funny story...
My husband is a bit of a klutz. Well, actually, that's like saying a 500-degree oven is "a bit warm".
There are two points in the Jewish wedding ceremony where the bride and groom drink from a glass of wine. I was joking with my husband a few days before the wedding, that since he was such a klutz, he was going to be nervous, and I wanted my wedding dress to actually stay white, I was going to have a word with the rabbi and make sure the wine would be white, in case he spilled it. (He was not amused.)
At the appropriate point in the ceremony, the rabbi handed me the glass of wine. I hadn't noticed until I had the goblet in my hands, because it was a metal goblet, but it was in fact white wine. I took a sip and handed it to my husband...
He did a classic double take. He looked at the wine, looked at me, looked at the wine, looked at me... then took a sip. Our best man told us afterwards, that it seriously looked like he was having second thoughts about getting married!
As it happened, he didn't spill a drop.