This Computational Thinking challenge this year will run from March 9 to March 20. The challenge fits well with with the DTHM curriculum being implemented this year. 

Castors Years 4 to 6
Benjamins Years 7 and 8
Cadets Years 9 and 10
Juniors Years 11
Seniors Years 12 and 13

The challenge is available for the five divisions and teachers can apply to be their school coordinator. On the teachers tab of the site, there is a link to register, and a link to download coordinator instructions. (among other info!) 

Instead of a charge per student, there is a $50 charge per school regardless of the number of students who sit. And after the challenge, you will receive a solutions guide and an explanation of how the problems related to Computer Science. 

For more information