AEM 6 - Create .ics file dynamically and store on page

You can store data anywhere in the JCR - it does not need to be under the page to access it. In your page, use JQuery $( document ).ready(). When the page loads, call a backend servlet to get this data from the JCR, return the data to the page and set the data. 

If you are looking for code snippet, it goes like this. But keep in mind that your approach of storing a file on load(GET method) violates REST principles.

 Node folder = myResource.adaptTo(Node.class);

JcrUtils.putFile(folder, "myfile.ics", "text/plain", instream);

folder.getSession().save();

Thank you for the help. 

I implemented the code using a servlet. Every time the "download ics" button is clicked, the request goes to the servlet which creates the file and sends it back. I have set the following properties to the servlet response :

response.setContentType("text/calendar");
response.setHeader("Content-Disposition", "attachment; filename=event.ics");
response.setContentLength(cal.toString().length());
response.getWriter().print(cal.toString());

and i get the following output when i check the response in chrome/mozilla developer mode: 

BEGIN:VCALENDAR
PRODID:-//Event Calendar V1.1//EN
VERSION:2.0
CALSCALE:GREGORIAN
DESCRIPTION: Event Description
BEGIN:VEVENT
DTSTAMP:20150323T143849Z
DTSTART:20150422T093000
DTEND:20150423T190000
SUMMARY:Event Title
TZID:America/New_York
UID:20150323T143849Z-uidGen@fe80:0:0:0:0:ffff:ffff:fffe%11
END:VEVENT
END:VCALENDAR

But I still it does not download the ics file. 

I could not understand your use case why you want to store, because you might have some events not every one subscribed Or applicable to few users. So far with  implementations generally created on fly & pass in response using FoldingWriter of ical.

http://build.mnode.org/projects/ical4j/apidocs/index.html?net/fortuna/ical4j/data//class-useFoldingWriter.html

FoldingWriter foldingWriter = new FoldingWriter(response.getWriter(),....;