ADIOS Amigos: Galactic Explorers

Couch co-op Delta V for kids (and grown ups). If you've been looking for a way to impress your kid with your knowledge of orbital dynamics, this is it. It's awesome to execute a Hohmann transfer from a planet to a derelict space station, disconnect it's AA power core, then try to snake it back out of the station to steal its energy before the powerless satellite crashes into the sun. It's not a perfect game, but they did an amazing job balancing the simulation so it's fast enough to not be boring, but never feels _completely_ out of control. "Never" may be too strong — see "crashes into the sun".