If you've seen any of the Popups API videos, then you know how slick this API can make your site.
The really nice thing about the Popup API is how easy it is to implement in other areas of your site (other than the ones that are provided by supporting modules). The module's latest README.txt file is a great starting point, for this this tip, I'm going to suggest a method that anyone can implement.
Simply add the CSS class "popups" to any link on your site and it will open in a popup (be sure to check the "Scan all pages for popup links" option on admin/settings/popups).
There's several other ways to implement popups that integrate a bit "deeper" with Drupal, but this method is a great way to get started.