Please take a look and provide feedback!
This feature has come about after Afforess provided excellent proof-of-awesomeness in his NS++ tool with "Live Happenings".
There is also a related Happenings API currently in testing.
Ballotonia tells me I should emphasize that this tool is not quite as real-time as it may appear, and thus not an Ultimate Game-Changing Anti-Invasion Device like you might think. In particular, its results aren't any more real-time than the existing Reports page, except for the fact that it periodically auto-refreshes, which saves you from having to press F5. The data can be delayed anywhere from 0 to 30 seconds, or even more, if you leave the screen open for a long time.
The main aim of this feature is to make visible the vibrancy and activity of the world, and especially in your own region.
EDIT Ballotonia:
PAGE IS NOW LIVE
New URL: http://www.nationstates.net/page=activity