Okay, I've got one. It's not cake related, but funny (now).
When one of my sisters got married, my other two sisters, a friend and I went EARLY to decorate the reception hall. My dad and some of his friends also went. Well, after us girls did our part my dad told us to take my uncle's station wagon and go home and get ready (knowing that his wonderful daughters take forever to get ready
Anyway, we're on our way home when all of a sudden smoke start coming from the car. This is pre-cell phone era, so here you have four girls who know nothing about cars, no cell phone and a particularly deserted highway since it was early Sunday morning. Luckily, these two ladies in a truck pass by and stop and help us. We asked them just to take us back to the hall because we figured my dad and his friends would still be there. Well, we get to the hall and it's all locked up and they've already left. These two ladies were SUPER nice - they took us all the way home (and we lived a pretty good distance from the hall). Oh, and did I mention it was a truck? So on the way home, you have four girls (one with curling pins in her hair - me) in the back of a truck next to a truckload of groceries. When we finally got home my sister (the bride) could have eaten us alive - she thought we had stopped at McDonald's for breakfast.
Oh, and also on her wedding, we lost the car rental keys right when we had to leave, realized we left the bouquet in the car right when it was time to throw it, and the night before her wedding my sister my rearended by this out-of-town guest!
I guess some people would not take all those things happening on a wedding day as a good sign, but that was 10 years ago and my sister and her husband are still going strong with their fifth kid in tow!