Maybe a little hard to believe but there is a group of hardy souls who have a tradition of swimming in the Serpentine on Christmas day ,come rain,wind or snow.More at http://golondon.about.com/gi/dynamic/offsite.htm?zi=1/XJ&sdn=golondon&cdn=travel&tm=19&gps=211_907_869_598&f=00&su=p284.8.150.ip_&tt=2&bt=0&bts=0&zu=http%3A//www.serpentineswimmingclub.com/christmas_day_race.htm