Can I play sports with my turban on?

There should be no problem with wearing the turban in most sports.  

Karate

-       May wear religious mandated head-wear of type approved by the World Karate Federation

Soccer

-       A player may use equipment/clothing other than the basic equipment provided that its sole purpose is to protect him physically and it poses no danger to him or any other player

-       According to FIFA, religious headgear is not considered dangerous and are permitted.  Turbans should match uniform colours in some jurisdictions.  

Basketball

-       According to FIBA, Sikh players may wear religious headgear.