Making a program that intercepts network traffic in Windows

Sort of what I'm asking is "how to make a software firewall for Windows," but something not so complex. I'm surprised I can find so little when searching for this, only the occasional mention of hooks. So it'd be much appreciated if someone could point me in the right direction.

I expect to do this with C (though if there's another language you think would work better, I'm all ears). I want to make an application that watches network traffic, can extract the IP address (source for incoming, destination for outgoing), and can block said network activity.

This seems like something that would be much easier to do in the kernel, but I don't want to be mucking around in there, nor do I even have access to do that in Windows anyway. I'm not worried about efficiency, nor am I looking to make a personal firewall. This is just for an experiment regarding IP addresses.

Any pointers?

Note: It's important that I be able to block network certain network activity too, not just monitor it