Today and tomorrow the (virtual) doors of the Maker Music Festival are open.
People showcase various electronic and acoustic instruments they built - really interesting and inspiring!
https://www.makermusicfestival.com
A schedule with the live sessions can be found here: Maker Music Festival
From the acoustic instrument side I am particularly fascinated by some of the creations from Bart Hopkin - some really cool stuff:
http://barthopkin.com/