heroku_demo.js

fab = require( "fab" );
appCount = 79353;

with ( fab )

( fab )
  ( import, html )
  ( listen, 0xFAB )
  
  ( route, /^\/$/ )
    ( HTML, { class: "heroku" }  )
      ( HEAD )
        ( STYLE )( "body { font-size:200% }" )()
      ()
      ( BODY )
        ( H1 )( "Welcome to Heroku" )()
        ( DIV )
          ( B, { id: "appcount" } )
            ( appCount.toString() )
          ()
          ( BR )
          ( "apps running right now" )
        ()
        ( SCRIPT, { src: "/update" } )()
      ()
    ()
  ()
  
  ( route, /^\/update/ )
    ( serverCount )
  ()
  
  ( "Not found.", { status: 404 } )
();

function serverCount( write ) {
  function clientCount( count ) {
    var d = document, s = d.createElement( "script" );
  
    d.getElementById( "appcount" ).innerHTML = count;
    s.src = "/update?" + +new Date;
    d.body.appendChild( s );
  }

  return write( function( write ) {
    return fab.stream( function( stream ) {
      setTimeout( function() {
        var s = "(" + clientCount + ")(" + appCount++ + ")";
        return stream( write( s ), { headers: { } } )();
      }, 0|( Math.random() * 3000 ) );
    });
  });
}

this is just a short app i threw together for a demo @ heroku... scales to, uh, 1 user.