I've just discovered that Atlassian is giving away a full-featured license of JIRA and Confluence at the incredible price of $5 each. It is a fully functional license, the only limitation is the five-user limit.
If you are interested, you don't have too much time to make a decision. It's a time-limited offer and it expires tomorrow.
I have been using JIRA and Confluence in a couple of projects. As an open source project, the Zend Framework benefits from a free license of the full suite. It's a shame this offer doesn't include Crucible, I'm really looking forward to trying it.
Although I'm a really happy Redmine user, I don't rule out the possibility of purchasing a license. It could be useful, sooner or later…