You need to look under the community menu and then select 'member leagues'.  There are various different ones on a drop down list and there is a tick box to join up if you fancy it.

That's great.  Yes, its so addictive and there's always another challenge to go for.  Its also so nice just feeling fit and active.  Have you been calculating your age grading percentages?  That's another nice motivation - and there are our member leagues!

Wow Tosh!  That is an impressive lifestyle change!  I'm glad you've caught the running bug which can be addictive in itself, but luckily a generally healthy addiction.