We used an Entertainment Book while in Hawaii, and saved close to $200, mostly on 2 for 1 specials. It is available from http://www.entertainment.com
for about $25/30.
Also, since I don't anticipate going back to Hawaii in the next 6 months (although I would like to), if anyone is interested in buying my Entertainment book for $20, you can e-mail me at: firstname.lastname@example.org
Still lots of coupons available, including helicopter discounts