Being a rum/rhum/ron lover I couldn't pass on hitting distilleries while visiting the 4 main islands - and to be perfectly honest where at first I was only aware of Koloa Rum from Kauai because it was sold in the stores of Chicagoland area, as we got closer I learned that each of the the 4 biggies produce their own rum but this place in Oahu was the richest, fullest and best experience one can get from a distillery when it comes to the "sugar cane poison" :) I am speaking here after seeing about 25 to 30 rum/rhum/ron distilleries in my life - this place is the real deal.
You start with a freshly squeezed sugar cane juice - delicious! - then comes the sugar can variety garden and info on which ones they use for their rhums (their rotate and switch from one cane to another making the bottle content even further unique), then their aging facility is open to you, and bottling (behind the glass window) where you can also "smell" the work-in-process product being distilled, and lastly the best part - the sampling. You get to enjoy their 4 rhums - Kea, Kokoleka, Koho and Kila - and for $10 extra upgrade you can do on the spot as well, you get to try their Koa rhum.
Each rhum we tried was delicious, I love agricole rhum! For those who aren't familiar and come here just for something "different" the agricole rhum is made from sugar cane juice vs. molasses so it takes completely different than the typical "Bacardi" rum you are used to in cocktails, it sips differently and mixes differently - it's a more "noble" product as its made from the actual juice as oppose to a byproduct of sugar, giving it a very specific flavor like no other.
You can buy the bottles on the spot and for $25 USD engrave them with a logo of your choice from their catalog + whatever you want to write on them = a lovely sovenir from a special trip, we both loved the place and appreciated big time, despite only 1 of 2 of us being a fan of this "poison" :)
TIP: you can buy their bottles on the island/islands but I have only seen Kea and Kokoleka - even Costco in Kauai carried Kokoleka for the same price (didn't track the stores, but many places in general in our experience around 4 big island charged more for their product on the spot versus what you could find them for in say ABC Stores FYI)