Fritzing is an open-source electronic design tool
If fritzing gets #1 spot on HN I would like to wholeheartedly recommend https://www.kicad.org/ as well.
IMHO much saner workflow and good UX in the latest version.I did a simple PCB and got it manufactured on https://jlcpcb.com/ 
for a couple bucks. Quite a rewarding experience.I would also suggest that anyone who cares about computers gets to know basic electronics. How do transistors work, what is a bus (e.g I2C or SPI) and how is it all connected? (Drumroll ... a PCB of course). There is a ton of tutorials on youtube that do it end to end. E.g Phils Lab https://www.youtube.com/watch?v=rLDqQ2L_mUQ for a PCB design. Or Ben Eaters excellent beginner tutorial "Hello World from Scratch" https://www.youtube.com/watch?v=LnzuMJLZRdU