We visited Williamsburg last summer. On the Busch Gardens web site they had an excellent deal on a 7-day pass. You could go to the amusement park and/or the water park as much as you wanted for a 7-day period, beginning on the day you validated your pass by entering your first park. The price was great. If I remember correctly, it was less than two 1-day admissions. Since we were going to spend one day at each park, we basically got the option for some extra days (which we used for short waterpark visits) for free. We did pay for parking each day we entered a park, though. Still, we were very happy with this deal.