I'm in a bit of a productivity rut and whilst I suspect the issue is mainly between the keyboard and chair I'm also interested in what (FOSS) tools there are that people find effective.
One of my issues at the moment is cross managing different workstreams particularly with personal projects which are more in the "if I have time category".
I'm interested in anything that helps manage time or limit distractions or anything that makes it easier to keep track of progress/next steps for project when there may be a bit of a time gap between.
For keeping track of tasks on my projects i use todo txt. For each of my projects will drop a file named todo.txt in the root. each line is a task, and i order them based on priority. I can walk away from it and when i start working on the project again, i have an simple way to see the list of tasks i have laid out for this project.
http://todotxt.org/
I personally find it less useful to see the "big picture" of all tasks, and this lets me focus on the details of my projects without forcing a bunch of structure.