Escape from City 17
Escape from City 17 is a short film directed by the Purchase Brothers. It is based on the Half Life series but more specifically on Half Life 2. The story takes place during a very turbulent time in City 17 and as such, it's assumed that it takes place after the events of Half Life 2 with the Citadel going critical. Of course there is also the possibility the film is a depiction of the Seven Hour War, but is unlikely due to the presence of a Citadel (which would take time to build and assuming seven hours of war would not be enough) and the fact that the City 17 citizens the movie follows appear just as the rebels within Half Life 2 (and its subsequent episodes) which would likely not be garbed in ammo and lambda symbols within such a short span of time with the Combine presence.
The film (both part 1 and the currently unreleased part 2) were created with a substantially small budget of $500 considering the production qualities the Purchase Brothers managed to meet. Most (or all) of the film's sound effects were created using the Source SDK's resources. There are also animated 3D models within the movie which are assumed to be from the Source SDK as well or at the very least based upon Source SDK resources. From this, it can be said that the Purchase Brothers' film is an example of how extensive the use of the Source SDK can be within other mediums besides game modification.