gistfile1.css

.list_even {
	background-color: #F5F5F5;
}

.list_odd {
	background-color: #DFDFDF;
}

gistfile2.html

<% @et_users.each do |etuser| %>
  <tr class="list_<%= cycle('even','odd')%>">
    <td><%=h etuser.UserID %></td>
    <td><%= link_to 'Show', :controller => 'eldertech', :action => 'show', :id => etuser.UserID %></td>
  </tr>
<% end %>