First, check your terms of service. Bypassing this block may violate them.
Second, are you really prepare for exposing your home network to incoming traffic? Are you ready to manage all the security required? Can you handle it when a security crack creates a bot network or site hosting illegal material in your home and your ISP and/or the law show up to discuss it?
Third, there are a variety of free or very low cost services for you to host your own blog ranging from blogger to wordpress.com to livejournal for basic blogs to full fledged hosting services like Dreamhost (usually under $10 for the first year) to Grokthis.net ($6 month for fairly nice services).
Unless you have a real business reason to host it at home and the expertise necessary to administer a network at that level, spend the $10 or less a month. You'll save yourself stomach lining and probably money in the long run.