Per various reports on Twitter, Rusty Hardin, the defense attorney for Roger Clemens, has requested that the judge declare a mis-trial after prosecutors played a portion of a video that included testimony about Andy Pettitte's wife that the judge had already ruled could not be put in front of the jury.
Hardin objected, the jury is in recess, and the judge, based on the reports on Twitter, seems inclined to grant the defense motion for a mis-trial, expressing concerns about "unringing the bell" and instructing the jury to disregard what they just heard.
If a mis-trial is declared, the jury will be dismissed and the trial will have to start all over again. When? No telling, but generally speaking, these things don't start back up again for many months.
The judge said he wanted to confer with a colleague and is, as of this post, still not back on the bench. Once he comes back and there's a ruling, this will be updated.
UPDATE -- ESPN is reporting that the judge has declared a mis-trial.