ClockingIT is a free to use, Time and Project tracking solution written in Ruby on Rails.
The sources are available as well as a hosted version.

Features

• reports and time tracking
• due dates and timelines
• search and tagging
• actvity log and timeline
• notifications, like rss and iCal
• there are no restrictions or limits
• an integrated wiki
• different languages (english, brazilian, french, german, spanish and norwegian)