For those who frequently find themselves around a prominent and well wired coffee chain try setting your user agent to this:
User Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0)
App Name: Microsoft Internet Explorer
App Version: 4.0 (compatible; MSIE 7.0; Windows NT 6.0)
Restart your browser and there should magically appear a link to a Windows Vista Promotion. Enjoy your free wifi until April 30th.