In the spirit of this thread, here are some more public projects from HNers on DoerHub:

http://www.doerhub.com/for/bluetooth-sensor (arduino research)

http://www.doerhub.com/for/theodinproject (tech ed)

http://www.doerhub.com/for/lumihealth (health insurance)

http://www.doerhub.com/for/robopaint

http://www.doerhub.com/for/coincashcard (bitcoin)

http://www.doerhub.com/for/crowdfunding

http://www.doerhub.com/for/synaptor

http://www.doerhub.com/for/you3dit (3D printing)

http://www.doerhub.com/for/www-roomva-com (latam hotel app)

http://www.doerhub.com/for/stemfunder

http://www.doerhub.com/for/surgery-boards-app (surgery ed app - in beta)

http://www.doerhub.com/for/securityfirst (human rights)

http://www.doerhub.com/for/vizhack (visualisations)

http://www.doerhub.com/for/pilgrimr (beta testing)