US National
There's currently only one truly national online poetry calendar, at the Academy of American Poets Web site.

US Midwest
Illinois, Iowa, Michigan...

US Northeast
New York, Pennsylvania, New Jersey, New England...

US Pacific Coast
California, Oregon, Washington...

US Rocky Mountains
Colorado, Idaho, Montana...

US Southeast
Florida, Georgia, the Carolinas, Virginia, DC...

US Southwest
Nevada, New Mexico, Oklahoma, Texas...

Canada
Montreal, Toronto, Vancouver...

Britain & Europe
Dublin, Edinburgh, London, the Continent...