I know about 1/4 to 1/5 of them. For every Graham Norton and Jeremy Irons, there's a Hugh Quarshie or Carol Vorderman. Honestly, I don't care if I know who they are or not or if I like them or not. Some of my favorite episodes have been for people who I hadn't even heard of....or had a negative opinion of. I just enjoy the show. The fact that these people are in the public eye doesn't have much to do with it.