I just tested it and it works fine. Perhaps the site was down for some reason.
[15:44] <Goofy|AFK> !horoscope libra
[15:45] Sign & Dates: 07Libra (9/23-10/22) Today: 12Tuesday, January 4, 2011
[15:45] Quickie: 03Stay focused on the important things in life -- if it's not fun, it's not right.
[15:45] Overview: 03Your home life could use some shaking up, and while that's not exactly fun, it is still vital. Make sure that your family or roommates get the heads-up so you don't take them by surprise.