Retreiving the URL http://www.google.com/reader/api/0/token returns a token, which is periodically updated. What's required to generate this token? Apparently, and I'm guessing a, or some, cookies are accessed by Google for authentication.
Here are my results so far:
thufir@ARRAKIS:~/projects/curl$
thufir@ARRAKIS:~/projects/curl$ ruby token.rb
<html><head><title>403 Forbidden</title>
<style type="text/css">
body {font-family: arial,sans-serif}
div.nav {margin-top: 1ex}
div.nav A {font-size: 10pt; font-family: arial,sans-serif}
span.nav {font-size: 10pt; font-family: arial,sans-serif; font-weight: bold}
div.nav A,span.big {font-size: 12pt; color: #0000cc}
div.nav A {font-size: 10pt; color: black}
A.l:link {color: #6f6f6f}
</style></head>
<body text="#000000" bgcolor="#ffffff"><table border="0" cellpadding="2" cellspacing="0" width="100%"></table>
<table><tr><td rowspan="3" width="1%"><b><font face="times" color="#0039b6" size="10">G</font><font face="times" color="#c41200" size="10">o</font><font face="times" color="#f3c518" size="10">o</font><font face="times" color="#0039b6" size="10">g</font><font face="times" color="#30a72f" size="10">l</font><font face="times" color="#c41200" size="10">e</font> </b></td>
<td> </td></tr>
<tr><td bgcolor="#3366cc"><font face="arial,sans-serif" color="#ffffff"><b>Error</b></font></td></tr>
<tr><td> </td></tr></table>
<blockquote><h1>Forbidden</h1>
Your client does not have permission to get URL <code>/reader/api/0/token</code> from this server.
<p></p></blockquote>
<table width="100%" cellpadding="0" cellspacing="0"><tr><td bgcolor="#3366cc"><img alt="" width="1" height="4"></td></tr></table></body></html>
thufir@ARRAKIS:~/projects/curl$
thufir@ARRAKIS:~/projects/curl$ nl token.rb
1 require 'rubygems'
2 require 'curb'
3 token_url = "http://www.google.com/reader/api/0/token"
4 c = Curl::Easy.perform(token_url)
5 puts c.body_str
thufir@ARRAKIS:~/projects/curl$