Helping with DAViCal
The DAViCal CalDAV Server is free, open source software. This means that along with the software you can, if you choose, get all of the source code to the software and make changes to it yourself.
If you like this software, but find that it isn't quite the perfection you were hoping for, there are several ways that you can help to make it better:
Tell Us What Is Missing
It may sound obvious, but unless we hear about your problems we can't fix them. Until someone mentioned on Slashdot that they thought "taking over a whole virtual host" was a problem, it didn't occur to us that people might find that an issue, so we didn't fix it. When we found out, we made the (few) necessary changes to make it so.
Unfortunately we can't all be off reading Slashdot just on the offchance someone might mention something worth improving! So don't be scared: file a bug, or a feature request. There is no harm in asking.
If you follow the instructions to the letter then you might find that we have it wrong in some places, and you have to search for something, or maybe your setup is different to ours. You probably aren't unique, so it is really useful if you can throw some quick notes in the Wiki about where your experience differs from the docs. This is especially useful because we are not coming at any installation 'fresh', and we may not notice that what we do is different to what we wrote down!
If you are competent in English, and expert or native in another language, perhaps you can help with our translation efforts. Also, if you are using DAViCal in a different language and you see something that isn't translated, you can just send us the 'what it said' and 'what it should have said' and we will fix it.
There's more information about Translating DAViCal too, if you want to take on a whole language.
Write Small Plugins
If you want to use DAViCal, but want to authenticate against a different database then you might do this as an authentication plugin, which you can contribute back in it's entirety. That means that other people with similar requirements might be able to use your code, and they might even improve it, or ensure it continues to operate against newer versions of DAViCal. There are some preliminary docs regarding Pluggable Authentication but they could do with some clarification. Ask questions on the mailing list, or just directly within the page, if this isn't clear.
And, of course, you can write code. The source code for DAViCal is there for all to read, and we're happy to answer any questions about it or point to particular things that you could do which would be good introductory problems if you want to get further involved. Here's the start of some Help For Developers that could do with a little more work, for starters!
Tell Your Friends
If nothing else, if you like this software then tell your friends about it. Maybe you don't feel you have the time or skills to help out, but your friends, or their friends might, and if we get one person helping for every thousand users we'll be doing better than most proprietary software packages.