Knebworth's been cancelled, so me and 16 friends are left with a mini bus and a spare weekend. How can we fill it?

The obvious choice would be Brighton, and I'm not against that

But what else is there? Preferably somewhere that you could have a decent day and THEN night, before getting picked up at around 6am to go home (we could always bring this forward)

Milton Keynes? Ashby-de-la-Zouch?