Alternatively, you could do something like:

```ruby
class Challenge < AR::Base
  def user_with_yellow_jersey
    users.order('activity_total desc').first
  end

  def yellow_jersey? user
    user_with_yellow_jersey == user
  end
end
```

Then in the view you can have:

```erb
<td>
  <%= link_to user.preferred_name, user_activities_path(user) %> <%= image_tag 'yellow_jersey_small.png' if @challenge.yellow_jersey?(user) %>
</td>
```