0 A.D. is a free and open-source real-time strategy video game under development by Wildfire Games. It is a historical war and economy game focusing on the years between 500 BC and 1 BC, with the years between 1 AD and 500 AD planned to be developed in the future. The game is cross-platform, playable on Windows, macOS, Linux, FreeBSD, and OpenBSD. It is composed entirely of free software and free media, using the GNU GPLv2 license for the game engine source code, and the CC BY-SA license for the game art and music.

A Let's Play (LP) is a video documenting the playthrough of a video game, often including commentary and/or a camera view of the gamer's face. A Let's Play differs from a video game walkthrough or strategy guide by focusing on an individual's subjective experience with the game, often with humorous, irreverent, or critical commentary from the player, rather than being an objective source of information on how to progress through the game. While Let's Plays and live streaming of game playthroughs are related, Let's Plays tend to be curated experiences that include editing and narration, and can be scripted, while streaming is often an unedited experience performed on the fly.