HTTPS reverse proxy for HTTP-only web service

I have a Windows web service application running on HTTP, no HTTPS support. Can someone recommend some lightweight HTTPS reverse proxy in front of it, so connections to it from the outside can go through HTTPS?

From serverfault CyberShadow

• One of the most light-weight tools to SSL enable a http, or other, service is stunnel.

  sysadmin1138 : Totally worthy. It's a good fit.
  From Zoredache