Today, I have a very simple game that came across my Facebook wall. The game is called 2048.
What you'll have before you is a 4x4 grid, in which two of the boxes are filled with a number. The number will be a multiple of 2 (probably both 2's, though possibly there'll be a 4 in there). When you press one of the arrow keys on your keyboard, the numbers will slide as far as they can go in that direction, and then another number will appear in an empty box- again, probably a 2, more rarely a 4, never any higher.
Your task is to keep the grid clear by slamming identical numbers into each other. When you do, the two numbers will merge. The stated goal is to get to where you have a 2048 on the board (although you can keep going after that), which will require you to make a 2, then a 4, 8, 16, 32, 64, 128, 256, 512, 1024 and then the 2048. This will require you to fill the board up quite a bit before you can even begin to go for it. On my first and so far only playthrough, I only made it up to getting the 512 onto the grid.
An alternative way to play is to go until you can't anymore and simply add up the values of the boxes you have when you run out of room. In which case, I got 898 on my first go.