I recently had this idea for a new Drupal module that allows users to manage their sessions. The idea is that a user could look at their current sessions to see if any suspicious activity had happened on their Drupal account. They could then delete any sessions they don't like the look of in order to kill off that session.
The functionality I describe here is actually quite important as it allows users the ability to spot suspicious activity on their accounts. I have even used it in the past when one of my accounts was hacked. The fact that the session was opened from Brazil helped me inform the site that something was wrong.
I did some searching on Drupal for a module that did the same but didn't find anything so I thought I would create a module and go through the process of creation in an article. This includes the research into how this can be achieved in Drupal, looking at designing the interface, and then adding code to create the needed effect.