The Udderbelly is just fantastic.
There is a bar/cafe area outside with giant jenga and conenct 4 - just such a great place to hang out.
Underbelly | Southbank CentreThe London SE1 website has an excellent events list.
London SE1 :: South Bank, Bankside, Bermondsey & WaterlooMy own tuppence worth (as a London resident):
Go to the Royal Festival Hall. Have a coffee on the terrace overlooking the river.
Look for any free concerts in the Clore Ballroom or National Theatre. Walk along the riverside back up to the London Eye to see the street theatre performers - break dancers, statues, bubble blowing man. Absolutely tops for children.
Book your tickets at the Udderbelly for the evening.
Stroll back as far as the National Theatre, pop into the National film Theatre and ask for their free screening room - you get a session where you can call up archives of 1000's of film clips on a screen (shared headphones) for free.
Continue to stroll to the Tate Modern if you feel like it.
Tell you what, if anything at the Udderbelly takes your fancy Mrs Scum and I will come along. Any other YACFers?