London: walk around, shop, glass of champagne, shop, another glass, make it two glasses, show, a bottle of the same stuff.

Next day - lather, rinse, repeat. OK, if it's your first time in London, squeeze in a museum trip, but... don't forget a glass of champagne beforehand.

Other ingredients:
Food is optional.
Sleep is minimal - catch up on a plane ride going back home.
Young, errr, younger English lads (or lasses, whatever strikes you fancy) are strongly recommended for getting introduced to local culture.

browsing unique travel sites when putting together a surprise b-day trip for one of my girlfriends