LONDON — The athletes and the Olympic torch have arrived in London - and so has the party. For those keener on celebrity-spotting or dancing the night away than medal counting, the British host city has plenty of action to offer during games time. Away from the track and field, Hollywood royalty such as Brangelina and Nicole Kidman will be rubbing shoulders with diplomats and businessmen at the city’s glitziest clubs and grandest historic buildings. Meanwhile, Dizzy Rascal, Snow Patrol and other musicians will keep crowds entertained at outdoor concerts across the capital — though there won’t be cocktails and canapes.