"Twilight" star Robert Pattinson and Jimmy Fallon play "Water War" during a taping of "Late Night With Jimmy Fallon." Plus, Fallon and Carrie Underwood stage a country hoedown; Kristen Steart and Garrett Hedlund pitch "On The Road" at New York screening; stars come out for the 2012 Soul Train Awards in Las Vegas; Adam Levine, Christina Aguilera, Cee Lo Green and Blake Shelton headline a red carpet event for "The Voice" Season 3; and Ricky Gervais, Robin Williams and other comedians come out for the 6th Annual Stand Up For Heroes.