What I really loved is that how easy it was to write directly to the video buffer (320x200 256), it was ultra fast and I could even make simple games and shiny stuff :) Not sure if it's possible to do that outside dosbox anymore.
I made a resistor ladder DA convertor, and then wrote data to the parallel port with a few simple BASIC "OUT" instructions.
https://groups.google.com/forum/#!topic/sci.electronics.basi...
https://hackaday.com/2014/09/29/the-lpt-dac/
Some GB emulators (NO$ at least) used this for sound, and it was quite good.