Scheduling queries to run when sql server is not busy Is it possible to schedule some queries not for specific times but to run when sql server is not busy?

Is there any way to calculate the business of the sql server?
An Idle condition is defined at the SQL Agent properties, Advanced

https://msdn.microsoft.com/en-us/library/ms189065.aspx

The select it in the schedule type for the job as Rafael said in his comment