lock net access with router password?

I have a WGR614 v8.
Is it possible to configure my router so that every time anyone tries to go online, no matter what the device, a password must be used?

Something I could turn off and on would be ideal.

I have teenagers that don't feel the need to pitch in around the house, as a consequence I want to control the privelege of internet usage.

Any help would be greatly appreciated.