AD&D, MUDS, MMORPGs, etc.
The burst of the fireball does not expend a considerable amount of pressure, and the burst will generally conform to the shape of the area in which it occurs, thus covering an area equal to its normal spherical volume. [The area which is covered by the fireball is a total volume of roughly 33,000 cubic feet (or yards).]
A modern version of the old Rogue/Nethack type of dungeon exploration game. Open source and web accessible.