[olefoo]

You can't monetize it without it being a business. So accept that and manage it like a business; decide how much time you want to devote to it and what are acceptable revenues to justify the time you are giving it.

Look at different business models and pick the one that works for you. If you want to hang ads on it, do that. If you want to work with the certifying authority for the sport and have the sports association pay you a yearly fee to provide the software to all official events, start investigating if that's possible. If event promoters find value in the software figure out what they are willing to pay for it and sell them licenses ( yearly, per event, lifetime, whatever works ).

Don't half-ass it by thinking you aren't in business, fully ass it by making it _your_ business.