Currently GetAwayToday is having a deal where if you purchase a 3-day hopper pass, you can get a free upgrade to a 5-day 1 park pass. A hopper pass lets you go back and forth between Disneyland and California Adventure as many times as you want, with a 1 park pass, you get the park of your choice each day, but only that one park. We have decided to opt out since we love hopping back and forth, and because Dalan has to eat Plaza Inn Chicken at least once a day while we are there.
Here is a link to purchase:
You have to purchase by today, but you can use the ticket anytime before December 31.