The most obvious reason a geek should study acting is to become the one geek out of millions who actually has social skills. There are other reasons as well (I've blogged about them before). But this is a great reason:
The big difference between good acting and bad acting is authenticity. Learning how to act forces you to recognize that difference - how could you measure your progress without a metric? Anyone in a large corporate environment can benefit from learning to distinguish between authentic and inauthentic communication.
It's not even just a matter of corporate politics, though. Think about requirements gathering. Plenty of people will pretend to understand you or agree with you if they think the alternative is looking stupid. That accidental intimidation can result in bad requirements gathering, but if you can spot it, you won't be fooled by it. You can take a second to acknowledge their brains so they feel better, and then ask the question differently so you get the real answer.
There are tons of geeks abusing this social phenomenon, most of them unknowingly. The excuse is always blaming the user for their inarticulateness or their stupidity. But if people are dumber then you are, then you should be able to figure out what they think - especially when they're trying to tell you.
By the way, if the whole "Why Geeks Should Study Acting" trend in my blog is boring you, don't worry, I am planning to get to "Why Geeks Should Study Latin And Ancient Greek," as well as "Why Geeks Should Study Kung Fu" and "Why Geeks Should Study Fencing." I just haven't got to that part yet. Over the course of this blog I will in fact justify everything I've ever done in my life, proving for a fact that everything I've ever done is something every geek should do - even the time I got arrested in Vegas with $300,000 in a vinyl bag and somebody else's goat in my car. I'm going to call that "Why Geeks Should Get Arrested In Vegas With $300,000 In A Vinyl Bag And Somebody Else's Goat In Their Car."
In the meantime, just one more little thought: as different as computer programming and acting are - as jobs, as careers, as ways of thinking and being - there's one fascinating point of intersection between geek culture and drama culture, which is Dungeons & Dragons.
Both geeks and actors love D&D, though you might not actually hear about it, because both geeks and actors are prone to treating D&D like this big guilty pleasure. I've even worked in offices where talking about the recreational pharmaceuticals you enjoyed when you were young was a less daring and candid move than admitting that you played D&D last weekend. It's kind of silly like that.
If you're down with this idea that geeks should work on their social skills, but not down with the idea of destroying the geek culture - because there is, after all, beauty in the geek culture - D&D gives you a nice safe middle ground, and, if you're lucky, a nice safe middle ground which can involve actors as well as geeks. Worth thinking about. Also, if you're a programmer who plays D&D, you're in good company.