You can wrap it like this:
<% @tasks.each do |task| %>
<li id="task_<%= task.id %>">
<%= link_to task_path(task.id) do %>
<h2><%= task.task_name %></h2>
<p><%= task.task_content %></p>
<% end %>
</li>
<% end %>
You could be even fancier and create your html tags with content_tag
<% @tasks.each do |task| %>
<li id="task_<%= task.id %>">
<%= link_to task_path(task.id) do %>
<%= content_tag :h2, task.task_name %>
<%= content_tag :p, task.task_content %>
<% end %>
</li>
<% end %>
Hope it helps :)