These Balls Are Made For Hiding is your browser game for today.
You're presented with a black field, which conceals invisible circles. You can fire a straight line into the field, which will bounce whenever it hits a ball, or when it hits certain walls. You can take as many shots as you like; once you're happy with one, you click to remove all the balls touched by that shot. Every time you remove balls, all the remaining balls in the field move downwards. If any balls touch the bottom of the field you lose.
So very simple, so very addictive. It doesn't seem to be on any of the good game portals but you can play it at the rather ugly page I'm linking to here.