Another rock'n'roll Xmas

This could turn into one of those classic British movies, with a Hugh Grant or James Nesbitt thrown in...
Get 4,200 people to dress up as Santa, invite them to a small Welsh town for a charity fun run, let a few sneak off to the pub, watch those few get a little 'merry' and then swap punches, and then throw in the riot police with CS spray and batons drawn...
You couldn't make this stuff up.