These are some "easy ports" that are potentially good GHOP tasks:
<ul>
<li><a href="http://drupal.org/project/bbcode">BBCode</a></li>
<li><a href="http://drupal.org/project/blockcache">Block Cache</a></li>
<li><a href="http://drupal.org/project/commentrss">Comment RSS</a></li>
<li><a href="http://drupal.org/project/diff">Diff</a> (see this issue for a gotcha: http://drupal.org/node/154144)</li>
<li><a href="http://drupal.org/project/flickr">Flickr</a> (issue: http://drupal.org/node/197367)</li>
<li><a href="http://drupal.org/project/issues/feedburner">Feedburner</a></li>
<li><a href="http://drupal.org/project/google_cse">Google Custom Search Engine</a></li>
<li><a href="http://drupal.org/project/me">"me" aliases</a></li>
<li><a href="http://drupal.org/project/menutree">Menutree</a></li>
<li><a href="http://drupal.org/project/smileys">Smileys</a> (issue: http://drupal.org/node/166089)</li>
<li><a href="http://drupal.org/project/user_badges">User Badges</a></li>
</ul>

And some features:
<ul>
<li><a href="http://drupal.org/node/197367">User Badges module: Views integration</a></li>
<li><a href="http://drupal.org/node/75927">User Badges module: User Points integration</a></li>
<li><a href="http://drupal.org/node/121521">User Badges module: optimize queries by adding indices</a></li>
</ul>

Now, let's hear the criticism on why some (hopefully not all) of the above isn't eligible as a GHOP task. If I'm completely missing something, point me to the stuff I should read.

After I've had some comment on this, I'll start writing the <em>actual</em> GHOP tasks (including basic gotcha's for every module to port).