NGINX has been discussed here some but if you are looking for an open source Windows or Linux load balancer or reverse proxy it might be worth a look.
In particular I use it on a Windows server to reverse proxy a Xojo Web App. It manages the certificates and I put the Xojo app up on an internal port that does not have to be SSL. If you are having a hard time scaling a CGI app this might also help you easily scale with a stand alone Xojo Web App.
I subscribe to some email notices from these guys and I just got a notice for a Webinar on June 12 that is an overview of their open source and paid product.
Here is the link to that Webinar and some others if you want to sign up.