Create outlook appointment files

I want to know if there is any application or way to create .ics files on mac.
I am running a site and I want to be able to offer ready-to-be-installed files to my visitors, directly to their outlook/calendar application(windows).

I want to be able to create such files so that every visitor of my site would just click on link with .ics file, and a date/time appointment will be added to their outlook/calendar application, if they choose to do so. Just as simple as that.

How can I do it?

 

Thanks!