Brian,
I can only speak for longhaul at BA. On short trips most of the time you'll be left to do your own thing as far as the cabin crew go. The other pilot(s) you'll be with will (virtually) always go for a drink at the other end as a minimum. When I first joined BA I found the fact that the crew hide themselves away as one of the hardest things to get used to. Maybe I'm a sensitive little flower but in my previous job we'd usually go out as a group which of course could make for some very amusing evenings. At BA however the majority of cabin crew seem to lock themselves away in their rooms, order room service, watch tv or if they're feeling a bit crazy maybe go shop or lie by the pool.
The majority of longhaul crew are 35+ and have been flying for at least 10 years. As a relatively young guy I'm more often than not the youngest of the crew. Don't get me wrong, most of the cabin crew are really lovely people and I've had plenty of fun nights out, I'm also fairly junior so don't do some of the longer trips which I'm sure would be more fun from a socialising point of view. My only gripe is that there's not more of a spread of ages as I think this would really energise the crew. Also, on the 777, if you need a tonic from 40 year old women going on about child care, HRT, slagging the company etc, you can fly out of Gatwick which is an altogether different experience, far more sociable, vibrant and more like what you'll be used to in any other airline in the UK!