Below is a sample config for Lighttpd that
seems to work well on Debian Squeeze, with "lighttpd/1.4.28 (ssl)"

The idea is: if someone enters the bare URL for my site, 'example.com',
they get redirected to https://example.com/index.html, which is simply a
page with two links on it: https://wordpress.example.com and
https://friendica.example.com.

If someone enters https://example.com, they get redirected to
https://wordpress.example.com/main/, which is the 'main' blog in a Word
Press 'network install' of the 'subdirectory' variety.

I thought it might be nice to offer people who join my Friendica
instance their own blogs, if they like.

One can obtain free, signed, single subdomain SSL certificates from
StartCom CA, which upon checking I noticed was already installed in both
Firefox and Google Chromium.  Info at http://cert.startcom.org/ .  So I
got one for each site, and have Lighty use the appropriate cert based on
the requested URL.

Enjoy!

---------------( config starts )-----------------

debug.log-request-handling = "disable"
debug.log-condition-handling = "disable"

server.modules = (
        "mod_access",
        "mod_alias",
        "mod_compress",
        "mod_redirect",
        "mod_fastcgi",
        "mod_rewrite"
)

server.document-root        = "/var/www"
server.upload-dirs          = ( "/var/cache/lighttpd/uploads" )
server.errorlog             = "/var/log/lighttpd/error.log"
server.pid-file             = "/var/run/lighttpd.pid"
server.username             = "www-data"
server.groupname            = "www-data"

ssl.engine = "enable"
ssl.pemfile = "/etc/lighttpd/ssl/wordpress.pem"
ssl.ca-file = "/etc/lighttpd/ssl/ca.pem"

# Send everybody to landing
page:                                                            
$SERVER["socket"] == ":80" {

$HTTP["scheme"] == "http" {
    $HTTP["host"] =~ ".*" {
        # This next redirect doesn't appear to ever execute in
Firefox                       
        # (sometimes, anyway -- caching issue?), but it does seem
to                         
        # reliably in Google's Chromium browser. If I change it
here                         
        # and restart Lighty, Firefox still goes to the URL in
the                           
        # last 'else' below. Or something. 
Sometimes.                                       
        server.document-root = "/var/www"
        url.redirect = (".*" => "https://example.com")
    }
}

}
else $SERVER["socket"] == ":443" {

$HTTP["scheme"] == "https" {

    $HTTP["host"] == "wordpress.example.com" {
        server.document-root = "/var/www/wordpress"
        ssl.pemfile = "/etc/lighttpd/ssl/wordpress.pem"
        # include
"wpmu-rewrites.conf"                                                       
        url.rewrite-if-not-file = (
            "^/(.*/)?files/$" => "/index.php",
             "^/(.*/)?files/(.*)" => "/wp-includes/ms-files.php?file=$2",
             "^(/wp-admin/.*)" => "$1",
             "^/([_0-9a-zA-Z-]+/)?(wp-.*)" => "/$2",
             "^/([_0-9a-zA-Z-]+/)?(.*\.php)" => "/$2",
             "^/(.*)/?$" => "/index.php/$1"
        )
    }
    else $HTTP["host"] == "friendica.example.com" {
        server.document-root = "/var/www/friendica"
        ssl.pemfile = "/etc/lighttpd/ssl/friendica.pem"
        # Got the following 'Drupal Clean URL'after Mike suggested
trying                    
        # something along those lines, from
http://drupal.org/node/1414950                   
        url.rewrite-if-not-file = (
            "^\/([^\?]*)\?(.*)$" => "/index.php?q=$1&$2",
            "^\/(.*)$" => "/index.php?q=$1"
        )
    }
    else $HTTP["host"] !~ "(friendica.example.com|wordpress.example.com)" {
        server.document-root = "/var/www/wordpress"
        ssl.pemfile = "/etc/lighttpd/ssl/wordpress.pem"
        url.redirect = (".*" => "https://wordpress.example.com/main/")
    }
}

}

index-file.names            = ( "index.php", "index.html",
                                "index.htm", "default.htm",
                               "index.lighttpd.html" )

url.access-deny             = ( "~", ".inc" )

static-file.exclude-extensions = ( ".php", ".pl", ".fcgi" )

include_shell "/usr/share/lighttpd/use-ipv6.pl"

dir-listing.encoding        = "utf-8"
server.dir-listing          = "disable"

#compress.cache-dir          =
"/var/cache/lighttpd/compress/"                               
#compress.filetype           = ( "application/x-javascript", "text/css",
"text/html", "text/p\
lain"
)                                                                               


include_shell "/usr/share/lighttpd/create-mime.assign.pl"
include_shell "/usr/share/lighttpd/include-conf-enabled.pl"

---------------( config ends )-----------------