President Barack Obama has teamed with reigning NBA MVP Stephen Curry on a public service announcement calling for Americans to mentor youth in their community to make a positive impact. The video was shown Saturday on ABC's ''NBA Countdown'' ahead of Curry's playoff opener with the defending champion Golden State Warriors against the Houston Rockets on Saturday. Curry and Obama golfed together last August and Curry also visited the White House with the Warriors in February - and Obama mentioned Curry ''clowning'' with defenders the way he had been shooting. More...