Split a collection of items so that they can be displayed within two column divs

split_collection_into_columns.html.erb

<% number_of_columns = 2 %>
<div class="columns">
<% @things.each_slice((@things.length / number_of_columns.to_f).ceil) do |column_of_things| %> 
  <div class ="column">
<%   column_of_things.each do |thing| %>
    <%= thing.title %>
<%   end %>
  </div>
<% end %>
</div>

Using ceil to handle overflow from division, gives more flexibility, and allows the same pattern to be used for 3, 4 or more columns.