well, what happened was...
used to preceed an exaggerated story about a mistake/problem that could (usually) be summed up with a short, more accurate, explanation.
"well, what happened was... a dog saw a squirrel and ran three times around the tree and by the time I finished helping the dog, that's when my sister's car was stolen by Iraqi Ninjas. So I chased them down and punched one in the face, he burst into flames and then I got back into the car, drove here and that's why i'm late for work."