If you use the XMLRPC client in ruby over a self certified SSL you have this warning :

warning: peer certificate won’t be verified in this SSL session

You can get override that warning cleanly (i have seen some people who just comment the message in the standard library) like that :

require 'xmlrpc/client'

require 'net/https'
require 'openssl'
require 'pp'

module SELF_SSL
  class Net_HTTP < Net::HTTP
    def initialize(*args)
      super
      @ssl_context = OpenSSL::SSL::SSLContext.new
      @ssl_context.verify_mode = OpenSSL::SSL::VERIFY_NONE
    end
  end

  class XMLRPC_Client < XMLRPC::Client
    def initialize(*args)
      super
      @http = SELF_SSL::Net_HTTP.new( @host, @port,
                                      @proxy_host,@proxy_port )
      @http.use_ssl = @use_ssl if @use_ssl
      @http.read_timeout = @timeout
      @http.open_timeout = @timeout
    end

  end

end

if __FILE__ == $0
  f = SELF_SSL::XMLRPC_Client.new2("https://url")
  puts f.call("method", 'arg')
end