AllOut
Free Board Games for Kids: Online Strategy Game - With 50 boards to choose from, ALLOUT is a tough game indeed, and it will most certainly put those brain cells to the test. The objective of the game is to turn off each light on the board. By clicking the piece on the board, you will reverse the state for that piece and every adjacent piece. If they were "on" they'll switch to "off".
To win you just need to make sure the entire board is ALLOUT. If you are really stuck, you can click the Solve button; but beware, there is a price to pay for the solution. The first 4 levels of ALLOUT are classified as "Easy" to get you into the swing of things, from that point on you are on your own.
If this Flash-based game no longer works on IE11 on your PC / MAC, try playing on Chrome or Firefox browser.