I have knocked together a plugin to add a live activity feed to the front page. Every ten seconds it checks for new activity in the event log using ajax (no refresh needed), if there is a new entry it will be added to the top of the list and an alert will sound. It shows the 50 most recent questions, answers, comments and new users in the event log. I haven't added any settings but, if you know what you are doing you should be able to add more events, reduce/increase the amount of entires and so on. It's possible to add events such as profile changed, badge awarded and so on, check the event log in your database. It's not all my code, some was adapted from the recent events widget: https://github.com/echteinfachtv/qa-recent-events-widget
Anyway hope you enjoy.
Upload to the plugins directory.
Admin > Layout > Add Widget