The Christmas box office may have got off to a relatively slow start, but it is bouncing back at midweek. On Tuesday, for Example, Mission Impossible -- Ghost Protocol added $9.6 million to its domestic gross, which now stands at $86.2 million. Overseas it has earned another $170 million, bringing its worldwide gross to $256.2 million and restoring Tom Cruise's luster as one of Hollywood's top stars. Also performing strongly has been Sherlock Holmes A Game of Shadows , starring Robert Downey Jr. and Jude Law, which took in $7.3 million on Tuesday. With kids out of school, Alvin and Chipmunks Chipwrecked proved to be a contender with $6.8 million on Tuesday. But David Fincher's The Girl with the Dragon Tattoo , although doing respectable business on Tuesday -- $4.6 million -- has not lived up to expectations. In fact it earned only slightly more than We Bought a Zoo -- $4.2 million -- which was expected to flop and did.