Wrike - Wrike is a flexible, scalable, and easy-to-use collaborative work management software that helps high-performance teams organize and accomplish their work. Try it now.
Scrumpy - A simple, beautiful and agile project management software
Leantime - Lean project management for startups & small teams
Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.
Producteev - Producteev is a free task management application for individuals and teams to collaborate via the web, email, IM, mobile or desktop.
Nifty - Manage projects, work, and communications in one place.