Index: wp-includes/formatting.php
===================================================================
--- wp-includes/formatting.php	(revision 9826)
+++ wp-includes/formatting.php	(working copy)
@@ -964,6 +964,16 @@
  * @return string HTML A element with URI address.
  */
 function _make_url_clickable_cb($matches) {
+	// If the URL string started with a ( and ended with a ) then
+	// don't include the trailing ) as part of the URL.
+	$last_char = '';
+	if( $matches[1] == '(' ) {
+		if( substr( $matches[2], -1 ) == ')' ) {
+			$matches[2] = substr( $matches[2], 0, -1 );
+			$last_char = ')';
+		}
+	}
+
 	$ret = '';
 	$url = $matches[2];
 	$url = clean_url($url);
@@ -974,7 +984,7 @@
 		$ret = substr($url, -1);
 		$url = substr($url, 0, strlen($url)-1);
 	}
-	return $matches[1] . "<a href=\"$url\" rel=\"nofollow\">$url</a>" . $ret;
+	return $matches[1] . "<a href=\"$url\" rel=\"nofollow\">$url</a>" . $ret . $last_char;
 }
 
 /**
@@ -1035,7 +1045,7 @@
 function make_clickable($ret) {
 	$ret = ' ' . $ret;
 	// in testing, using arrays here was found to be faster
-	$ret = preg_replace_callback('#([\s>])([\w]+?://[\w\\x80-\\xff\#$%&~/.\-;:=,?@\[\]+]*)#is', '_make_url_clickable_cb', $ret);
+	$ret = preg_replace_callback('#([\s>(])([\w]+?://[\w\\x80-\\xff\#$%&~/.\-;:=,?@\[\]()+]*)#is', '_make_url_clickable_cb', $ret);
 	$ret = preg_replace_callback('#([\s>])((www|ftp)\.[\w\\x80-\\xff\#$%&~/.\-;:=,?@\[\]+]*)#is', '_make_web_ftp_clickable_cb', $ret);
 	$ret = preg_replace_callback('#([\s>])([.0-9a-z_+-]+)@(([0-9a-z-]+\.)+[0-9a-z]{2,})#i', '_make_email_clickable_cb', $ret);
 	// this one is not in an array because we need it to run last, for cleanup of accidental links within links