It's Never Too Late for Wodify.com classes!
CrossFit athletes scheduling their courses with wodify.com might be familiar with this problem. You want to join a class spontaniously but it is full. You can put yourself on waitlist but the moment you recognise the notification mail for an open space it's already taken.
With this extension you just leave your wodify.com calender list view open and start the extension. As soon as a space is available you will automatically take it!
Technically this extension will only reload your Wodify.com calender list view tab every 5 Minutes and will book all classes that you are waitlisted on and are now available again. No witchcraft at all!