Winterfest was the Christmas celebration they had at Kings Island for several year. In fact, the Festaus was built especially for Winterfest and they eventually used it during the summers for the figure skating shows that were once there.
In short, they had International Street open along with select areas of the park. Lights were strung down from the top of the Eiffel Toweer to creat the world's largest Christmas tree. The fountain on International street was made into an ice skating rink. There was a living nativity in the Tower Gardens and carolers around the park. There were shows in what is now The Paramount theatre (then called American Heritage Music Hall) and the Festaus. As far as rides, the train operated along with the antique cars and Phantom Theatre/Smurf's Enchanted Voyage. Winterfest was discontinued the year after Paramount bought the park.
I would imagine if they were planning on resurrecting Winterfest they would have made an announcement by now. But I guess anything is possible
Cris