If the mass-murder of children isn't enough to actually do something about gun control, I don't know if we'll ever have the courage to do anything.

At least start with background checks, eliminating the gun-show loophole. Then an assault-weapons ban would be nice. Nothing good can come from unstable people having guns. And you don't hunt deer or protect your family with assault-weapons. If you like cool gadgets, get a PS3, or noise-cancelling headphones, or something.

Today, as you noted, there was also an elementary school assault in China, where private gun ownership is prohibited. Some kids were horribly injured by the knife attack, but no one was killed. Guns do make it much easier to kill people. The defense of "Guns don't kill people. People kill people" needs to be retired. It's as idiotic as "Fried food doesn't make you fat ... unless you eat it."
I know it's easy to say guns aren't the problem if you haven't been in this situation. But people need to put themselves in the shoes of the children who survived, who will live the rest of their lives with the scar of losing their best friends while their social development was just beginning. And think of the parents, some of whom may not have other children and may not be able to have another in the future. Their children were everything to them. Their lives were built for and around these kids who were stolen from them by a lunatic with a near military-grade weapon. And the teachers, many of whom grow to love and care for their students almost as if they are their own.

If you don't think we need more gun control, try to see it from the perspective of these kids and parents. That's a good rule, not only in this situation, but for life in general. Try to see things from the perspective of the victims, not the unaffected.