Here is a list of agile kanban tools, some of which you can self-host (open source): http://agilelion.com/agile-kanban-library/agile-kanban-tools

Interesting, I was thinking about building something like that a few weeks ago. Due to long commute hours I need something both online but that still works offline.

What came up to my mind was a dropbox based solution.

Didn't go further so far, though