Add every race on the Active.com, USAT calendar, trifind. I know you depend on members to add races, but if one day was spent a month going through those three places and condensing all of the races to your calendar, it would make your calendar hands down the best.
Are you volunteering?
Not sure about trifind, but wouldn’t Active have an incentive to help since they collect $$ on registration fees? You’d think the same for USAT. Not an software engineer, but I would think some kind of aggregating software wouldn’t be too hard (like Sidestep - the fare aggregator) to put in place.
If this were a non-profit site, I might… OK, even then I wouldn’t volunteer, but for a bit of money, I would be glad to keep the calendar up to date with every race posted on the internet.