I had to set up a customer's Rails application to run using SSL+HTTPS this morning. Based on a few positive web blog articles I decided to try Igor Sysoev's nginx web server. If you first build and install OpenSSL and the Perl regular expression library, then build nginx with
--with-http_ssl_moduleyou should be all set to use HTTPS. Clustering mongrel is also simple; I used this nginx.conf file from Brainspl.at as an example and I was set up and running very quickly. Good stuff!