Well I would say the social sciences are pretty broad so maybe narrow it down a bit for us? Generally though I would say go onto google and put in as many combos of your field and the words meeting/seminar/conferences etc you can and see what appears... It is sometimes a bit hit-and-miss. Maybe there is a lovely list out there I am in social sciences though and not come across it yet! Or you may be able to try your dept secretary? They may get info about this kind of thing and be able to name a couple for you to get you started. Or your sup, obviously. Some of the journals for my field also have conferences... Dunno about yours though but a lead nonetheless!!
hope this helps a bit.