X-Day (エクスデイ, lit. Ekusu-Dei), is a quiz arcade game that was released by Namco in 1993 only in Japan; however, not much is known about it due to the fact that it is not emulated upon MAME, apart from the fact that a sequel named X-Day 2 was released in 1995 (and even though this sequel game is emulated in MAME, it's the only Namco NA-1 game that doesn't work properly, and is unplayable).
