A general rule of thumb for this question is that most insurance follows the car not the driver. In this case, if you are a licensed driver, who does not have insurance, you will be covered as long as the owner of the vehicle has insurance. The owner of the vehicle must also give you permissiion to take the vehcile and you have not been excluded from the policy.
Another important thing to note is that this cannot be part of a routine. For you to be covered, it must be a rare driving occuance. It cannot be a weekly scheduled thing, such as you taking the car every Thursday. If it is part of a routine, then for you to be covered you must be on the insurance as a occasional driver, which will raise the rates.
It must be noted that every state / province is different with regards to their laws, and likewise every insurance company is different. it is best to always check with your insurance company and the insurance company of the person’s vehicle you wish to drive to ensure that you will be covered.