If you're looking for a simple time-tracking tool with visuals that are easy to read at a glance, Yast fits the bill.
Yast can track multiple projects and tasks each with their own colour code. The week-at-a-glance view is great for seeing how projects are unfolding over the week. You can generate reports and save them to your computer and invite other people to see your projects. The other notable advantage of Yast is inviting people to view and collaborate based on on the individual project, not the entire tracking calendar — your co-workers will never know that you've spent 39 hours in October organising your Pokemon collection.
Yast is free and requires registration. Have a time-tracking tool or service you love? Let's hear about it in the comments. Thanks, Mark!