Mine was Sega Outrun, on a shady XT PC with 1 color Hercules Monochrome display. It ran at a blisteringly quick 12 MHz (with turbo enabled, otherwise a more civilian 4.7 MHz).
Here's what it looked like more or less, except imagine it being different shades of green:
Needless to say I played it into the ground!
The other one was testdrive. We're talking testdrive 1 here, as in the first ever rendition.
I still remember it now. You got to choose between a Porsche 911 Turbo, Lotus Esprit, Lambo Countach, Ferrari Testarossa and I think a Corvette. I thought it was the best game ever...
Got no screenshot of it unfortunately.
EDIT:
Got some shots from Testdrive 1 and 2:
Here's what it looked like more or less on ye olde trusty Hercules Monochrome:
Here's my favorite Testdrive 2 car: