From a Gentle Reader:
"Mr. Dog, I have a question for you. Not being a smartass, I'm truly looking for a more rational response to the Sandy Hook shooting than "arm the teachers", "take away all the AK-47s" or "make it harder to buy and register guns". If I understood the reports correctly, none of those would have helped much. A teacher having a gun and taking a basic firearm safety and usage course doesn't make them a good shot. Frankly, if someone put a gun in my hands my students would be in more danger than whomever I was trying to shoot at, and I'm not alone. (I can aim and shoot a crossbow or a longbow, but a gun? I'm hopeless.) Those weapons were legally owned, registered, and used by Lanza's mother. That her son would steal them, murder her and then to go the elementary school was perhaps predictable, but only in hindsight.
And yet these sorts of atrocities are happening more and more. What is currently being proposed seems like over reaction on both the anti and pro gun sides, but what would you suggest?
The simple and honest answer? These sorts of atrocities are not happening more and more.
The Curry School of Education has a paper up called "School Violence Myths", in which Myth #4 states that school homicides have been trending downwards from a high of 42 in the mid-90s to two in the most current statistics.
Even MSNBC -- no friend to the Second Amendment -- points out that schools assaults have dropped "by nearly half in the past decade".
Reason.com has an article up titled: "Five Facts About Guns, Schools, And Violence", with embedded links and video.
Reason.com also has an article up which directly addresses your concern, titled: "Are Mass Shootings Becoming More Common In The United States?" with a very good graph.
Mass shootings are not on the rise, and haven't been for ages. What has changed, however, is the sheer amount of coverage these atrocities are garnering (deliberately, in some cases) leading to the incorrect perception that they are happening more and more.
Which is a whole other post.
Hope that helps,