How do I implement "enable" or "disable feature" similar to Drupal Gardens?
What you see on that page is a Drupal form where the form fields have been heavily themed to appear differently from how you would normally see that type of form field on a Drupal site.

Looking at the HTML source of that page, it is clear those selectors are simply checkboxes rendered with a custom theme function.

&lt;div class="form-item" id="edit-features-28711-wrapper"&gt;
 &lt;label class="option" for="edit-features-28711"&gt;&lt;span class="feature-icon" style="background: url(/sites/default/files/connect.png) no-repeat center center;"&gt;&amp;nbsp;&lt;/span&gt;&lt;input type="checkbox" name="features[28711]" id="edit-features-28711" value="1"   class="gardens-feature-checkbox" /&gt;&lt;span class="label-text"&gt;Follow us&lt;/span&gt;&lt;/label&gt;&lt;div class="feature-preview"&gt;&lt;img class="preview-image" src="/sites/default/files/stay-connected_0.png" /&gt;Gain a following. Provide links to your (or your users') profile on Twitter, Facebook or other social networks.&lt;/div&gt;
&lt;/div&gt;


There is also custom JavaScript code that changes the appearance of the form field.

When I turn off a feature, I see a CSS class being added to a tag, and another tag value being changed. The value associated with the checkbox is not changed; it is 1 when the feature is enabled, and it is still 1 when the feature is disabled.