Donate your next bike ride to Red Nose Day. Ride your bicycle for fun and fitness and make a pledge for each mile that you pedal (suggestion: $1 per mile). Bonus: Encourage friends and family to match the amount.
If you ride with a cycling club, donate to match the total miles from your next group ride--or create your own group ride with family and friends. Do you spin at your gym? Donate a set amount for each minute you spin, and encourage your classmates to do the same.