That's a bit of an understatement. It was over a minute before it even started doing anything. I'd turn on debug mode to see which queries are slow (and the twitter/Facebook stuff will slow it down) but I think you should start by pinging your server.
As Rob suggested, enable debug mode by adding this line to your library/config.php file:
$config['debug'] = 1;
That will add load stats to the bottom of the page, as well as a link to fully explain the queries on the page. That may help to isolate the bottleneck.
You should also check your server load. Run the "top" command on your server to see load stats. Maybe your server is out of memory or has a process that is hogging CPU cycles. The "top" stats may reveal this.