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.

Deck - A multi-timeline viewer for GitHub repository events

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.

JXL for Jira - The power of Jira with the familiarity of spreadsheets

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

Kanbanier - Clean iOS and Mac kanban/trello with flexible views