While some of these demos might end up getting re-published to the Demo channel down the line, that isn't guaranteed; they'll disappear from the Xbox Dashboard once the event ends on July 17th. As such, those interested in checking out any of the demos that are being added for this event will have a limited time to do so. Hopefully the full list of 40 games will have a good variety, and will give Xbox users a chance to play something they might not have otherwise!