Create a game with a sprite for the background (I used space) and a spaceship (vehicle). Have the ship move up (give it a velocityY of ___ ). If it gets to the top of the screen, have it appear at the bottom again. If they hit the space bar down, have it rotate around and go in the opposite direction (again if it gets off the screen, have it appear at the top) Photo link
You do not have to create what I have. What I want to see is 2 balls bouncing around the scene (bouncing off the edges). And 2 other sprites (whatever you want). Where if a ball hits the boy (or whatever), it bounces. If it hits the monkey (or whatever, the ball pushes the monkey off the screen.
Make frogger the most basic will have a character at the bottom of the screen. There will be at least 6 moving obstacles as shown with differing speeds. Some cars will move to the left, others to the right. When they get off the screen they will appear on the other side. The character will need to get past all of them and reach the other side. When she does, the score goes up by one, the cars move a bit faster.