Sometimes, you look at the sky and it's such a good day to go swimming. Then when you smack the trunk's elastic band around the waist with the satisfactory "piak" sound, the clouds turn grey and you stare dejectedly down at ya trunks.

Sometimes, you think it's going to rain and you tell yourself there's no point going to swim today. Then the sun comes out but you're already nuaing on ya bed.

So what is the best thing to do to keep fit?