If they are video files, then you can store them as attachments. However, you would probably have to increase the maximum attachment size to cope with vide files.
If they are stored somewhere else, and you access the videos via a url, then you can create text fields with type=url to store the urls. You could either create these fields on the campaign entity (if you have a known maximum number of videos per campaign),
or create a child entity with this fields (if you want an indefinite number of videos per campaign)
Microsoft CRM MVP - http://mscrmuk.blogspot.com/ http://www.excitation.co.uk