As announced recently for Gmail, we are launching support for internationalized email addresses in Google Calendar. This will allow people to use email addresses that contain accented or non-Latin characters to invite guests and share calendars, and perform any other action where email addresses are used by Calendar.
This includes both the domain name (to the right of the @ symbol) and/or the local-part (to the left of the @ symbol), as in 武＠メール.グーグル.
Release track: Rapid release and Scheduled release
For more information: G+ Post