For real DIY audio on PC, try the covox. It's a resistor based "dac" for the paralell port that we used to build as kids too before we could afford a proper sound card.
You could also buy a commercial version if you didn't want to solder [1]
You could also buy a commercial version if you didn't want to solder [1]
The one linked in the parent is a PCI card, so this might not apply.
One of them is running openbsd and I think it might be fun to write a driver for it actually. I see OpenMSX also support covox.