If you're not a fan of official sports apps like me, then the new AssistantExtensions addon called SiriSports might be what you're looking for. The jailbreak tweak enables Siri to deliver sports scores and schedules for the NBA, NHL and MLB.
SiriSports is located for free in the BigBoss repo. Once installed and enabled in Settings, you can ask Siri things like: "What's the score of the Knicks game" or "Did the 76ers win last night?" Siri will then give you the latest or final scores of the game you're looking for, instead of suggesting a web search.
I had a little trouble getting Siri to tell me the final of the Portland Trail Blazers / New York Knicks game from last night, but maybe you will have better success. To prompt the SiriSports tweak just say "NBA scores help." Siri will reply "to get NBA scores you can say things like..." followed by a list of examples.
SiriSports requires a jailbroken iPhone 4S or an older device using Spire.