Let me summarize with high tone legal analysis as to what just happened happened.
Judge: "Hey, prosecutor, do not make any reference to any statement of Mrs X where she says she believes her husband, Mr. X. I know that you are going to use the testimony of Mr. X who will say Clemens told him that he, Clemens, used performance enhancing drugs. I'm not going to have Mrs. X improperly bolster her husband's testimony by saying she believes Mr. X."
Prosecutor: "Gotcha judge!!! Sounds fair to me! I'm a federal prosecutor so I'm well prepared and will play by the rules! Promise!"
Judge: "Ok, then."
Prosecutor: "Judge, may I roll that beautiful bean footage of Clemens testifying before Congress? It's great stuff!!!"
Judge: "You, may"
[Tape showing Congressman questioning Clemens]: "Mr. Clemens, Mr. X testified that you admitted to him of using performance enhancing drugs, and I'm holding an affidavit of Mrs. X who says she believes her husband."
Judge (who palm slaps his forehead): "Stop the tape. Get the jury out of here. [Jury removed]. Mr. Prosecutor, you are so dumb. For sure."
Defense lawyer: "Can I have one of those mistrial thingies?"
Judge: "Boom! Granted!"