The first tour we did after arriving in Iceland was Grayline Tour's "Taste the Saga," billed as a brewery tour, but really giving you so much more bang for your buck.
"Taste the Saga" was unlike any brewery tour I've ever been on. Usually you spend the bulk of your time actually in the brewery learning about the hops, mechanics, and techniques used to create different beer with perhaps a complimentary pint at the end. After a bus picked us up from downtown Reykjavik we were transported to the Olgerdin Egills Brewery (there are two major beers in Iceland, Viking and Gull, Egills creates the latter) where we were lead directly past the manufacturing floor and into what seemed to be a very sterile conference room. There ended up being nothing sterile about it, as within ten minutes we'd already been given an entire bottle of Gull and Snorri (their new microbrew, which was delicious).
The tour was much less about the process of brewing as it was about the process of Icelandic drinking and the interesting history behind it. We learned about Vikings, Icelandic prohibition, and how to toast (Skal!) while downing the aforementioned drinks as well as Polar Beer (get it), a disgusting beer substitute that got Icelanders through the Prohibition and a shot of Brennivin, an Icelandic schnapps.
The best part was the tour guide, a sort of one-woman show who drank with us, frequently got off topic, and made us laugh the entire time. It was the perfect start to a Friday night.