I had half the class sit on one side of the tables (if we had those, or I had them go down every other row). Then I had the other half of the class sit on the other side (or on the empty rows.) When I called “Switch” (every 3 minutes- so they got about 2.5 to talk), they moved in a prearranged manner.
We did not get to all the people, but everyone met and talked to seven or eight people. I think that was a good way to get them to 1) talk and 2) get to know people. Plus, it was a limited amount of time and most of them found stuff to talk about so that they were surprised when it was over.
It worked to help them feel more relaxed in class.