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.

Google Calendar - Spend less time managing your day & more time enjoying it

Instagantt - Instagantt is a powerful and intuitive Gantt chart tool to enable teams to plan, manage and visualize their projects easily. Manage your schedules, tasks, timelines, and workload like a Pro. Try it for free.

Mixmax Calendar - The fastest way to schedule meetings with anyone, anywhere

Manifold - Manifold GIS is a combination of mapping, CAD, DBMS and image processing.

Sunsama - Calendar and scheduling for teams