From the AMC 8 website:
"The AMC 8 is a 25-question, 40-minute, multiple choice examination in middle school mathematics designed to promote the development of problem-solving skills. The AMC 8 provides an opportunity for middle school students to develop positive attitudes towards analytical thinking and mathematics that can assist in future careers. Students apply classroom learned skills to unique problem-solving challenges in a low-stress and friendly environment."
The AMC 8 is offered at schools and other sites around the country.
For more information, see the AMC 8 website.