Great Countdown widget here – http://www.onlinecountdowns.com/countdown-widgets/create?wstyle=7
One plugin which I found: http://wordpress.org/extend/plugins/widget-context/
To resolve this issue go to:
onb line 249 there is:
$this->hash_mailing_list_id($this->number) == $_COOKIE[$this->id_base . '-' . $this->number] || false == $this->ns_mc_plugin->get_mcapi()
Just delete this and write in the brackets
This should resolve the issue and load the widget every time.