Actually a lot do - look on the main page and you will often find a birthday or two listed, as people have put it in their profile.
Ajax103 do you really still get IDd!? I was once asked at 27 but that was in the States where the drinking age was 21.
Went to a pub for the annual Christmas dinner organised by some of my former colleagues and I went to place a order for a round of drinks only to be ID'ed, didn't think much of the pub not because of that but because the food was not even worth one star, McDonalds would have been better!
I remember getting stopped in Sainsburys in Great Yarmouth when I was 21, found a dvd for a fiver with a 15 age restriction, basically a WW2 film with Donald Pleasance and Michael Caine, went to cashier only for cashier to refuse to sell it as I was "under 15 yrs old".
Still brought it there after the store manager had to intervene after I complained.
Still, got my first Italian restaurant visit in two weeks time - really looking forward to it
, although If I were you I would be happy that I was asked for ID, although now that its the "Over 25 rule (but still 18 )" its a lot harder for people to see how old people are. 
