Atlassian software has a great deal available for 5 days – you can get a 5 person license to Jira and Confluence for $5!
I have experience of both products and think Jira is a grea issue tracker, and Confluence is a great enterprise wiki product. Both have their weak points (maybe biggest one being the fact the software is so flexible you can really shoot yourself in the foot by taking the customization too far), but I don’t think there’s better products in their class in the market. Even better, Atlassian folks are very pleasant to deal with and they’re one of the most open companies in their communication to the customers, which I respect a great deal.
Best of all, the money made with the offer goes to charity! So, go get your licenses now!