Thanks to the great reviews on Trip Advisor, my wife and I opted to do the Maui Pineapple tour. And we concur with everyone who said it was a great experience. I love pineapple and had some dim idea about where and how it was grown, but the tour was extremely interesting and informative. You tour the pineapple fields on a mini bus and our guide Mo did a great job in explaining the history of pineapple farming, how the pineapple grows, and how it's processed. And at the conclusion of the tour all guests on the tour are given a box with a couple of pineapples. Not surprisingly, they were by far the best pineapples I ever ate.
One suggestion--right across from the tour is a terrific restaurant, The Hali'imaile General Store. It's a bit pricey (but that's true for everything but fast food on Maui) but the food and service was excellent and well worth the cost.