One of my former colleagues always seemed to have his physics students in the hallway, in the stairwells, or outside for various physics demonstrations. His students always seemed to be having fun. I was a little jealous that he hadn't been my physics teacher too. He showed students that physics was fun. The following games might not be as fun as hands-on demos, but they could still be good for getting students interested in various physics concepts. 

Funderstanding, a learning systems design firm, offers a free roller coaster design activity. The object of the Roller Coaster Simulator activity is to get the coaster through the track without any roll-backs. To that end the Roller Coaster Simulator allows users to design the height and spacing of the rise and fall of a roller coaster track. Users can also adjust the speed of coaster, the mass of the coaster, the friction of the coaster on the track, and the strength of the gravitational pull on the coaster. 

Engineering Interact is a site for elementary school students designed by the Department of Engineering at the University of Cambridge. Engineering Interact offers five games designed to teach students physics concepts. The games address concepts related to light, sound, motion, electricity, and space travel. Each of the five games presents students with a scenario in which they have to "help" someone solve a problem. The games require students to learn and analyze the information presented to them. 

X Construction is an Android app that allows you to design railroad bridges and test whether or not they could support a train crossing. The app offers a series of progressively more difficult challenges to try. In each challenge level you are given a limited number of construction pieces to use in order to span an expanse that your virtual train needs to cross. When you think you’ve designed a suitable bridge press the play button to send the train over the bridge. If the bridge collapses you will see and hear a crash (warning, the crash sounds are bit annoying after the fourth or fifth try). If the train crosses your bridge, you can move on to the next level. X Construction could be a neat app for students to use to test out and see the benefits of various design concepts. For example, they can see why a triangle design might be superior to a square bridge design. 

Autodesk Digital STEAM Applied Mechanics is a free iPad app that contains five simple games. The games are designed to let students experiment with five connected physics concepts. The concepts in the games are energy and work, force, power, loading, and mechanisms. In each game students control one variable to see how changing that variable affects other aspects of the equation. The five games that students can play are Energy & Work, Forces, Power, Loading, and Mechanisms. In Energy & Work students control how much hot air is pumped into a hot air balloon as it is pushed along by the wind. Students have to manage the rate at which fuel is burned so that the balloon doesn’t run out of hot air before the end of the game. The Forces game has players using a catapult to lob meatballs (at least that’s what they look like to me). In the Loading game students use a crane to correctly distribute weight to waiting trucks. In Power players control the thrusters of a spaceship to navigate obstacles and safely land at a destination. And in the Mechanism game students maneuver a helicopter by controlling the ration of the gears powering the rotor. 

Hill Climb Racing is a fun Android game that has a little bit of physics built in. The purpose of the game is to reach the end of each level of the race. To reach the end you have to use your allotments of gasoline rationally. In order to do that you must control your acceleration and deceleration throughout the course. As you play through each level you can collect coins that you can then use acquire different tires and suspension systems for your vehicle.