I've never had a situation like this before, but the last 3 times I've been on, I suddenly disco - and it has always happened between 10-10:30pm. I get no warning signs like noticeable lag, or the "Lost UDP switching to TCP" (I may have the protocols reversed) message or anything - just bam and I get the Host Connection Lost box.
Ever hear of anything like that? My local provider is Mediacom.
Sometimes I log back in right away and ping the connection from the server selection screen, and it always seems to look OK.