Sorry, this is only for the U.S., but it could be a good way to win a set of bikes for you and your children, so you could embark on a healthier lifestyle. Georgia Pecans - Schwinn Sweepstakes (ends 6/30/16)

If you're outside of the US and are interested, just try searching on the specific terms you're interested in, plus 'contest' or 'sweepstakes' and your country, and hopefully you'll be able to find some you can enter.