Logged In: YES 
user_id=8719

attached is example extension file that can be used to get
calendars from roundup.  it works with issue item or index
views like this:

http://localhost:8917/demo/issue1?@action=calendar
http://localhost:8917/demo/issue?@filter=status,assignedto&status=-1,1,2,3,4,5,6,7&assignedto=username_or_id&@action=calendar

tested with calendar extension for mozilla firefox.