There are few good lightweight personal information managers available unless one is willing to use Emacs for everything. For some time I used remind as a console solution for my time management problems but at the moment I mostly use my mobile phones calendar function. Now I have to reconsider using a computer for time management as antiX provides a nice lightweight organizer application OSMO.
OSMO is very simple to use as all the main functions can be found in one window on six tabs. There are tabs for calendar, tasks, contacts, notes, options and information about the application. OSMO is included in the package repository of Ubuntu, so it is only a simple sudo apt-get install away from your desktop if you use Ubuntu!