Gran Turismo 2 - I have no idea why to this day, I play it atleast weekly. To me, everything about this game is timeless from the Soundtrack, selection of cards to the graphical style (it has to be played on a CRT mind you OR an emulator with some mods to fix textures and clipping properly.).
Epic pinball for MS-DOS, Specifically the Android table will forever be a core memory of mine. Any decent pinball games nowadays?