Weekend blockbuster blowout: Dark Knight vs. Mamma Mia?

Demand for tickets to the latest Batman film, The Dark Knight, is reportedly so high that movie theaters are offering showings at times like 2AM and 6AM on the first days of release.  Meanwhile, the Meryl Streep-headlined ABBA musical, Mamma Mia!, is already doing big business in the UK, knocking Will Smith's Hancock out of the top spot. 

Both films are expected to have big weekends in the U.S.