ScummVM is a free and open-source software that allows users to play classic graphical adventure games, provided they already have the game data files. It replaces the original executables of the games, enabling them to run on modern systems for which they were never designed. ScummVM is not an emulator; instead, it re-implements the game engines, offering improved portability and performance. The project supports a wide range of games, including titles from LucasArts, Revolution Software, and Adventure Soft, among others.