By Harvey Karten - Two movies about card playing opened in March. One, Zak Penn's "The Grand," features a number of A-list comics like Woody Harrelson, in a mockumentary about a poker tournament, but the dialogue is almost completely improvised. The other, " 21 ," is about the game of Blackjack at Vegas, which some believe to be the country's most popular gambling diversion. Peter Steinfeld's ...21 - Film Review (Arizona Reporter)