Hi there, Eldert! Thanks for getting in touch and welcome to the forums. I hope you’re enjoying the plugins so far. 🙂
Great question. I do want to note first of all, though, that we are fairly limited in terms of helping out with custom development questions like this one. That said, we’d love to point you in the right direction if we can.
One way to make this happen would be to customize the Upcoming Events template. There is more on how to create template overrides in our Themer’s Guide. In this case, you would make a copy of the single-event.php file (located in /plugins/the-events-calendar/views/list/single-event.php) and drop it into your theme directory in a new folder called tribe-events.
Once the file is in there, you can customize it to suit your needs. You can retrieve the ID for any Eventbrite event using the tribe_eb_get_id() function. This will allow you to construct the URL to your event on Eventbrite by echoing the ID in the URL (e.g. http://eventbrite.com/e/%5BID%5D).
Sorry I don’t have a concrete solution for you, but I hope this points you in the right direction. 🙂
Cheers!
Geoff