So I developed this quick application in C# which allows you to see some information regarding what packets are coming your way. Mostly this involves the average packet size and frequency of the packets (in bytes and ms respectively) - if your router's being attacked, simply forward the packets to your computer and run this program to see the IP of the attacker.
(this is a nice idea in theory, but don't ever open up your computer like that. Bad idea. Plus, getting the IP isn't guaranteed because false, crafted packet headers and proxies)
I uploaded a zip of it here if any of you wanted to check it out. May not be the prettiest or most well-coded thing in the world, but it was a fun experiment and it works to a degree :P
Now I kinda want to expand that and sniff the packets going through the network. What's the best way to do that? By using a MitM attack to get all the computers in the network to think i'm the router and then relaying the packets as normal. From what I can tell, the attack seems easy enough. Simply send packets with false header information saying it's from the router and break the connection between client and router, then when the client tries to find the new router tell them you're it. Though this again may be the whole theory/practice thing. We'll see :P