Desktop notifications are super cool.

http://caniuse.com/notifications
http://jsfiddle.net/dandv/wT26x/1/
https://github.com/ttsvetko/HTML5-Desktop-Notifications

Also merge with the feature where a support ticket plays a sound - just absorb the sound code, and drop the old polling code.
(Chrome won't play notification sounds right now)

Works like this...
A member may choose to turn on desktop notifications for various things. Many are on by default.
If a member has some, the member's browser regularly polls for notifications.
All notifications sent that apply as a desktop notification are logged into a database table.
If they aren't too old then they pipe to the browser.
We use a modified version of "HTML5-Desktop-Notifications" to play them.

Also have a block that can show these notifications, so we can tie it into the UI. If we do a redesign of the header area, this could be in a dropdown. Before then, it could probably be a footer icon (similar to bookmarks).