Pushing those old systems to their limit (and beyond) was a lot of fun and very instructional for those of us just getting into programming. On my Atari 800, I

Pushing those old systems to their limit (and beyond) was a lot of fun and very instructional for those of us just getting into programming. On my Atari 800, I recall using 6502 assembly to hook the horizontal and vertical blank interrupts to change the color lookup tables and character definition maps on the fly giving me the ability to greatly increase the number of colors displayed and do crude character-set animation.