Zuluru is an open source web-based sports league management application. It was initially specific to Ultimate Frisbee, but now also fully supports baseball, basketball, dodgeball, hockey, rugby and soccer, and is being expanded to other sports based on demand.
Zuluru aims to be easy to use for everyone, without sacrificing the flexibility to handle almost any situation. For example, players and captains get roster and attendance emails with links that work whether or not they are logged in to the site. The administrative side is more complex, but once your initial configuration is complete (e.g. defining your leagues and fields), there is very little weekly maintenance. Don't take our word for it; here are a few unsolicited testimonials from administrators in various leagues:
Just want to say love the website, we've been really happy and impressed with it so far. You have no idea how much better the admin side of things are with this website.
I hope you realize how much we appreciate your work and the awesomeness that is Zuluru. Please know that this site has made life SOOOOOOOOOOO much easier on us and the captains. We hear compliments on it a lot.
You've really done an awesome job with Zuluru. This is my first time convening and there wasn't time to train or guide me on anything... and I'm finding it hugely useful and extremely intuitive (and at times even patronizingly easy).
If you represent a league that needs help with hosting, administration and/or customization, please visit Zuluru.net.