What are some useful applications for university students?

I am looking for some interactive applications that can be downloaded to keep track of assignments, manage appointments, calculate class marks as well as overall GPA, etc.

I currently use Microsoft Outlook for most of my needs, so if there isn’t anything better in terms of scheduling/task listing/organizing, that’s okay.

But, I would REALLY appreciate a grade/gpa calculator. I need one that operates on % and number grade. Not letter grade.

Look into "Time and Chaos" as an organizer./