Advanced Countdown Clock - anysuggestions?

Advanced Countdown Clock - anysuggestions?

Looking for a script that will countdown to a pre-designated date, then
display a message for a designated period of time, then start a new
countdown to another pre-designated date.
In practical use it would work like this...
Begin Countdown to Monday 10th April at 5pm Display message : "Yay the
countdown has finished" for 2 hours Begin Countdown to Monday 24th April
at 5pm Display message : "Yay the countdown has finished" for 2 hours
and so on....
Ideally the time would be set to a specified time zone (not the users
computer) so GMT for example and as all of the predefined dates will
always be exactly 2 weeks apart the script should have some kind of
setting to deal with this instead of having to type up 30 predefined dates
in advance and hard code them into the script.
Not really fussed about which language it's in, php, javascript etc, as
long as it's easy to implement on a standard webpage.
Anybody know of anything out of the box that could do this?
Cheers