Critique my PowerShell tool!

My company has grown to a point that manually managing and creating “on call” schedules has become a major task.

This is one part to the ‘bigger picture’ I am building – thought I would share/ask for help so that I can improve. I have added detail to my code so that you can follow my train of thought during this process.

Script: http://pastebin.com/dugwdhyn

The output of above script: http://pastebin.com/7jmtrvwc