Spin is a form of bowling in cricket - generally an Indian specialty. The bowler sets the ball spinning, so that when it hits the ground and bounces back up, it can turn in one or other direction. Often, to a direction the batsman is not expecting. They’re slower balls, but really tricky ones to play.
“Dead rubber” is a general sporting term (that I hadn’t heard before) - a match that cannot change the outcome of the tournament (because it won’t affect the standings). In this match - a game in the Asian Cup 2014, India was already out, but they had another scheduled match, so they let the reserve players stretch their legs…