Here's the gist of it. Last Friday around 11:30 am, about 40-50 House Republicans were lined up to make 5-minute speeches before Congress adjourned for their 5 week paid vacation. This is routine stuff. Democratic Rep. Anthony Weiner (N.Y.) was controlling the gavel at the time though and wanted to get out of town. So he adjourned the house by voice vote (not a roll call vote) to silence the Republicans. (I am told there is video of this, will try to find it).
This outraged the Republicans. So they started hollering and yelling. Soon enough, under Speaker Nancy Pelosi's orders, the press gallery closed, the House microphones were shut down and the lights were turned off.