FUN TAX: A state proposal to tax entertainment has galvanized Orange County's big amusement businesses. Disneyland, Knott's Berry Farm, the Angels and the Rams have dispatched top-gun lobbyists or contacted state legislators to oppose the levy, which would raise $200 million statewide by applying the 6.5% sales tax to all tickets, from movies to ski lifts. . . . At Knott's, the tax would hike adult admission by $1.43.