You can add all types of content in the Long description of your events.
For content hosted on third party websites like YouTube, Flickr, SoundCloud, or SlideShare, just enter the URL of the video you would like to add. The media will be added automatically included to your event.
This also works for images, even if they are hosted on your own server: simply paste the image URL.
A list of the platforms' content that can be integrated in your OpenAgenda event description :
Click here to see an event example with integrated medias.