@Bkai, if you have NZBDrone setup on a linux machine running apache2 you could create a proxy for the calender which I did. You would use base64 authentication on your username/pass so no login is needed on the proxy.
Here is how:
Navigate to /etc/apache2/sites-available/
Edit the file 'default' (with nano or something like that, need sudo rights)
Just before the </VirtualHost> you can add the following:

Code: Select all

<Location /calender>
ProxyPass http://localhost:[nzbdroneport]/feed/calender
ProxyPassReverse http://localhost:[nzbdroneport]/feed/calender
RequestHeader set Authentication "Basic [basickey]"
@[nzbdroneport] = Enter the port of your nzbdrone setup
@[basickey] = Enter user:password encrypted with base64, use a site like this and input user:pass. This will give you a string looking somewhat like this: dXNlcjpwYXNz

After completing these steps you can go ahead and add http://[yourip/hostname]/calender/NzbDrone.ics into google.

NOTE: You can change the Location /[foldername] to anything you'd like!
Thought I'd post the nginx config I'm using if someone else wants to try it as well!

location /calendar {
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header Authorization '';
proxy_set_header Authorization 'Basic asdf=';