2x4 - What's New, Scooby-Doo?

The gang visits a state fair in order to see all the inventions "of the future." But they get more than they bargained for when they set their sights on a "House of the Future," which is allegedly haunted. Things seem pretty normal within... until Daphne mysteriously vanishes. Is it two prankster kids, a reality TV personality, the creator of the gadgets or the high-tech house of horrors itself that's responsible for the strange goings-on?