I use DDay.Ical, its good stuff.
Has the ability to open up an ical file and get its data in a nice object model. It says beta, but it works great for us.
Edit Nov 2016
This library has been deprecated, but was picked up and re-released as iCal.NET by another dev.
Notes about the release: rianjs.net/2016/07/dday-ical-is-now-ical-net
Source on GitHub: github.com/rianjs/ical.net