Texas Instruments Activities--http://education.ti.com/calculators/timath/
sign up for a emails of calculators activities, roughly these emails as sent monthly

Desmos, Free graphing calculator

Calculator Use on Exams Shift with Common Core Very good article about appropriate and strategic use of calculators and how testing decisions impact what is done in the classroom. I am in favor of allowing calculators on NeSAM for certain questions.
Counter argument to "Calculators = Bad" Blog about why calculators are important in teaching mathematics.
Comparison of calculator use allowed on major assessment as well as classroom use.
Calculator and Tools is a website with links on a variety of calculators and how they can be used.
Thinking About Calculator Use Blog post with a variety of thoughts

Estimation Calculator