"Hour of Code" is trademarked. We don't want to prevent this usage, but we want to make sure it fits within a few limits:
1. Any reference to "Hour of Code" should be used in a fashion that doesn't suggest that it's your own brand name, but rather referencing the Hour of Code as a grassroots movement. Good example: "Participate in the Hour of Code™ at ACMECorp.com". Bad example: "Try Hour of Code by ACME Corp".
2. Use a "TM" superscript in the most prominent places you mention "Hour of Code", both on your web site and in app descriptions.
3. Include language on the page (or in the the footer), including links to the CSEdWeek and Code.org web sites, that says the following:
“The 'Hour of Code™' is a nationwide initiative by Computer Science Education Week and Code.org to introduce millions of students to one hour of computer science and computer programming.”
4. No use of "Hour of Code" in app names.
You can download a high-res version of the logo here.