Some links:
Sheffield University Ceilidh Society (also runs a weekly session)
Exeter University Folk Society
University of Warwick Folk Society
Cambridge uni's "The Round"
Durham Universities Folk society
There also used to a Folked! society at UEA, I can't find evidence of them on the web at the mo though.

all these, plus a few other scottish societies attend IVFDF as mentioned by derek above, which is still mainly dance based, but there has been an increasing amount of concerts and sessions and music workshops during recent years. Not many sing- a - rounds though....

Jems