The H2Only challenge organised by the RNLI, returns for 2015 in a bid to raise vital funds for the charity who are called out to sea around 24 times a day. Participants who sign up commit to only drinking water for ten whole days. Think it sounds easy? Wave farewell to those frothy coffees that enables you to function first thing, those tea breaks that excuse you from your desk, and of course, those delicious after work bevs in the beer garden. To celebrate this year's challenge, a 'water-only bar' will also be popping up in east London to raise awareness of the campaign and recruit water warriors who are up for downing nothing but H2O. Find out more and sign up to take part here.