OK, the poll cleared nothing up. Since there was no clear cut favorite, I'm taking matters into my own hands.
I am going to name my pale ale after my favorite reaction I have never had a chance to run. I've always been a fan of
metathesis reactions, particularly
alkyne metathesis reactions. However, I have never had an occasion to run one.
I'm not sure why I like metathesis reactions so much, but the splicing of two distinct and potentially large molecules together to make a new molecule is really sexy.
I'm a big fan of
Fürstner's work with alkyne metathesis. I had the pleasure of driving him to and from the airport once. Shown below is his recent sythesis of Latrunculin A (I stole this from his website).

The biggest use of alkyne metathesis is in ring closing, as seen above. This is usually followed by Lindlar reduction to the alkene. The controlled formation of a Z-alkene is an advantage alkyne metathesis has over alkene metathesis which can result in E/Z mixtures.
A major disadvantage is that E-alkenes are difficult to form.
Birch reductions work great, but only in the absence of any useful functional group. When I was driving Fürstner to the airport in 2001, I asked him about this limitation. He just smiled a little smile and said, "we're working on it." That told me something was imminent. And it was. In 2002, Fürstner reported the following. Of course, at nearly the same time Trost reported a similar procedure. So it goes...

So, what does this have to do with beer?
Well, I am naming my beer: Metathesis Ale.
What's your favorite reaction you have never run?