PHPBB Countdown Timer & Calendar

I'm running an online gaming community with members from all around the world and we host regular online meet ups, events and competitions. For members to easily see exactly when the events are on, we require a multiple countdown timer preferably linked to a calendar to be prominently displayed on the website. We are using PHPBB 3.2.1 so the program would need to comply with their standards so as I can install and manage it the same as all the other extensions. I have attached a detailed document with all the required features, input and output features along with pictures and links to similar existing code. If I'm happy with how the project turns out, there will be more work in the future. (Video gallery, Show live streamers when online and an Award/achievement system along with some website modifications/colour changes etc)