Continuity mistake: Throughout the "Everybody Needs Somebody" song number, pay attention to the band member in the background smoking a pipe. More specifically, watch the smoke coming out of his pipe. Sometimes it's consistent from shot to shot, but at other times, it changes completely. (Ex. When Jake sings "When my soul's on fire," all of the smoke disappears between cuts).
Continuity mistake: During the mall chase, a semi-profile shot shows the squad car roll onto its roof and slide with a large panel of orange signage pinned under the roof. Camera cuts to a view of the officers inside the squad car, and there is no signage nor any other debris pinned under the car's roof. Camera cuts back, and the signage is again pinned under roof. Camera cuts back to frontal view, and the signage is gone again.
Continuity mistake: When the brothers are in the fancy restaurant, Elwood drinks champagne from a glass. A few shots later the glass is filled back up again.
Continuity mistake: In Ray's, the keyboard of the electric piano Ray plays alternates between being lit up and not lit between shots.
Continuity mistake: The woman in the car trying to shoot Jake has a couple of errors. First, she gets six shots out of a four barrel weapon without reloading. Second, she goes from having the weapon out of the window, to no weapon and driving in one second, where it took at least five or six seconds to get it out and aim it.
Continuity mistake: As Unit 10 slides along in the mall, it alternates from the front dragging on the floor, to only sliding on the roof in close ups on the cops.
Continuity mistake: When the Blues Brothers first go into the tax building in Chicago, the building has gold numbers above the door that they are blocking from the inside that read 118. When the rest of the cops and a firetruck pass by, we now see the numbers are black and not even the same shape as the gold ones.
Continuity mistake: When the cop car comes out to chase the Blues Brothers from behind the sign, the car starts off directly behind the sign. When the Good Ole Boys pass in the Winnebago, we see the cop car is before the sign and already has a running start.
Continuity mistake: After the cop car hits the Winnebago, we see the car's back window is completely gone in two separate shots. However, when the camera angle does a close up on the car, we see a cop pushing out the rear windshield which was simply not there the shot before.
Continuity mistake: At Chez Paul, when Jake and Elwood first meet up with Mr. Fabulous, who is talking on the phone, there is a shot of them walking down the hallway towards him and you can see that Mr. Fabulous is looking right at the two brothers. In the next shot, his head is down and he then looks up at Jake and Elwood.
Answer: It's 'Can't Turn You Loose,' often refered to as the Blues Brothers Theme.
rabid anarchist
Also done much earlier by Otis Redding.