Most embarrassing moment during a project presentation?

Question

Have you ever had such an experience such as during a presentation something goes wrong and you feel terribly bad and uncomfortable. How could you handle such a situation?

Answer 1

Do it like Steve Jobs:

Smile at the audience and say: "It's awesome when it works."

Greets Seb

Answer 2

I was once presenting some software to a customer, who was from the north of England, when I fell victim to my wandering accent syndrome and said "Now then!" in my best Bolton accent.

Fortunately he either didn't notice or was polite enough to not mention it. Still very embarrassing though.