This plugin allows you to add online videos to your game, which will appear on the game's menu both in LaunchBox and BigBox. Mainly, it supports YouTube and Steam videos. The videos get played by LaunchBox's portable VLC distribution, so you don't have to worry about having the right video player installed.
There is a new menu item on the game's menu in LaunchBox, allowing you to manage your game's video links, which can be seen in the following screenshot, along with two sample video links. Once you open the video manager dialog, follow the on-screen instructions (and click "More info") to add, edit or remove your video links.
In BigBox, the video links can be played from the game's "Additional Apps/Versions" menu, as exemplified here:
The project is available on GitHub.