I'll do a charity ride if it's close to home and there is an entry fee option in lieu of actual fundraising. I'm happy to donate, and have a couple causes close to my heart, but I'm uncomfortable asking.

If the minimum was $300 fundraising and I wanted to do the ride, I'd just donate the $300 myself (lots of organized rides cost more than that).

But Merlin, I do donate to a couple charities only because I have friends that fundraise for them. With an organized event you get a small army of volunteer fundraisers; that has to boost your charities exposure.