I did a fresh install of Ubuntu today and figured I would share the steps and packages necessary to get Ruby on Rails running.    I always miss a package or 2 and need to go back.   Here is what worked for me today.

Rails3 / Ubuntu 10.10 / MySql / Nginx / Ruby 1.9.2

Core packages

  
sudo apt-get install curl # RVM needs it and it is good to have
sudo apt-get install libcurl3-dev  # needed by several gems and nginx i think
sudo apt-get install git # RVM needs it and it is good to have
# Packages needed by rails and some popular Gems (also ssl for nginx)
sudo  apt-get install build-essential bison openssl libreadline6  libreadline6-dev curl git-core zlib1g zlib1g-dev libssl-dev libyaml-dev  libsqlite3-0 libsqlite3-dev sqlite3 libxml2-dev libxslt-dev autoconf  libc6-dev ncurses-dev
# MySql
sudo apt-get install libmysqlclient-dev  sudo apt-get install mysql-server
# needed by nginx
sudo apt-get install libpcre3-dev  #nginx

Install RVM

bash < <(curl -s https://rvm.beginrescueend.com/install/rvm)
#fix .bashrc then
rvm install 1.9.2  # or whatever ruby version you like
rvm --default use 1.9.2
gem install rails

Install Passenger/Nginx with SSL

Grab Nginx tarball

cd /tmp
wget http://sysoev.ru/nginx/nginx-0.8.54.tar.gz
tar -zxvf nginx-0.8.54.tar.gz

# install the gem
gem install passenger

# build Nginx
rvmsudo passenger-install-nginx-module

• Watch Phusion Passenger do its thing and when it asks you “Automatically download and install Nginx?”, answer 2
• Specify the directory where you unzipped the nginx source code (Please specify the directory: /tmp/nginx-0.8.54))
• Specify the directory where you want to install nginx to (/usr/local/nginx in my case)

You'll need a init script for nginx.  Get it here and follow directions

http://wiki.nginx.org/Nginx-init-ubuntu

To start Nginx use

sudo /etc/init.d/nginx start

Now at this point your nginx.conf needs some changes.  You need to point to your Rails apps and setup passenger.

Here is my http section for /usr/local/nginx/conf/nginx.conf .. this is a dev setup.  don't read too much into it.

http {
 passenger_root /home/tony/.rvm/gems/ruby-1.9.2-p180/gems/passenger-3.0.6;
 passenger_ruby /home/tony/.rvm/wrappers/ruby-1.9.2-p180/ruby;
 passenger_user_switching on;
include       mime.types;
 default_type  application/octet-stream;

 log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
 '$status $body_bytes_sent "$http_referer" '
 '"$http_user_agent" "$http_x_forwarded_for" "$http_host"';

 access_log  /tmp/nginx.access.log  main;
 sendfile        on;
 keepalive_timeout  65;

 server {
 listen       *:80;
 server_name  localhost;
 rails_env development;
 root   /<path to my rails app>/public;

  if ($request_method !~ ^(GET|HEAD|POST|PUT|DELETE)$ ) {
   return 444;  # block requests that Rails doesn't handle
  }
passenger_enabled on;
}
# HTTPS server
server {
  listen       443;
  server_name  localhost;
  rails_env development;
  root   /<path to my rails app>/public;
  if ($request_method !~ ^(GET|HEAD|POST|PUT|DELETE)$ ) {
    return 444;  # block requests that Rails doesn't handle
  }
  ssl                  on;
  ssl_certificate      local.crt;
  ssl_certificate_key  local.key;
  ssl_session_timeout  5m;
  ssl_protocols  SSLv2 SSLv3 TLSv1;
  ssl_ciphers  ALL:!ADH:!EXPORT56:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2:+EXP;
  ssl_prefer_server_ciphers   on;
  passenger_enabled on;
  }
}

restart your Nginx if it is already running

sudo /etc/init.d/nginx restart

That's all..  hopefully this helps someone.  :-)   My nginx.conf is much longer so hopefully I didn't cut out anything too important.