Metamagic Feat: Ray Extension
Source: Dragon Annual 5
You maintain a ray spell for an additional round.
Benefit: When the extended ray spell is cast, you can use your next action to attack with the same ray. You can designate either a different target or the same target. A successful ranged touch attack is required for the second target. If any other actions are taken, or the spell is disrupted before your next action, then you lose the extended spell (though any previous effects remain). An extended ray uses up a spell slot one level higher than the spell’s actual level.