I subscribed to my hotmail calendar in iCal a month or so ago. Worked great until about 2 weeks ago, when it suddenly stopped refreshing.
I removed the subscription, then tried to readd it. It then wouldn't subscribe, and asked me to 'check if I'm connected to the internet', which I was.
I took this problem up with Apple Support, who believe it is a problem with Hotmail instead.

Please rectify this ASAP, I need it for University.