I have been really into running for the last few years, but i bought a bike a few months ago after not having one for over 10 years, I must be doing at least 50 miles a week on it. Might knock the running on the head altogether, cycling seems to be a muchmore enjoyable way to keep fit.
Instead of 40 minute runs which drain my legs, batter my feet and bore me to death, my ticker gets a 2 hour workout which i enjoy. Its also a great form of transport.
What a genius invention it is.