<ul>
  <$list filter="[tag[Meeting]!sort[at]]">
    <li><$link to={{!!title}}>{{!!title}}</$link></li>
  </$list>
</ul>

If you happened to remember from an earlier exercise that the $link widget creates a link to the current tiddler if you don't give it any attributes or body text at all, you could also just say this:

<ul>
  <$list filter="[tag[Meeting]!sort[at]]">
    <li><$link /></li>
  </$list>
</ul>