I wrote this little thing tonight and got it working.
It scrapes nfl.com using requests / beautifulsoup and creates .ics files per team.
https://github.com/ericfrederich/footballcalendars
Get the .ics files here for NFL https://github.com/ericfrederich/footballcalendars/tree/master/calendars
Maybe I will try to add support for college teams, but I'm hoping someone else will fork it and do that for me while I'm sleeping ;-)