[Kwayzee the Clown]

I am just starting to learn some magic. I have the usual:Change bag, Magic hat w/compartment etc. My question is what do you do when you really mess up a magic trick and there is NO WAY that you can save it. For example a friend of mine was doing a cake production. He did not explain how, but in the middle of the patter the cake flung out and landed in the lap of the child's mom. He just went "Ta daaa, Happy birthday" and went on.
Of course the kids went crazy at that, but what if you mess up in a less spectacular fashion and your trick is exposed for all to see? One idea I have would to act really surprised, then a teeny bit embarrassed and explain that you have let a super magical secret out of the bag. then get all of the children(and adults, if any) to raise there right had and swear a silly sounding oath(working on one) swearing that they will not divulge the secret to any one. I believe that by being honest about the flub and by making the children de facto partners by sharing the secret should make them feel as if they are part of the show.
I would love to hear any other ideas in general or specific to a trick.

Kwayzee