Just clued in here... IGMP... Every minute...
IGMP is normal traffic. Your kernel listens to IGMP. It's used to figure out if there are any nodes listening on multicast groups so that all the routers can build their multicast tree. Every minute makes sense because that's the normal interval for a multicast enabled router. If you pull the packets into WireShark you might get a sense of which groups it's querying for.
The DoD source is a puzzling one. My most-reasonable-non-tinfoil-hat-guess is that Shaw is using addresses from that space for internal management or some loopbacks and that was the interface picked for the source address (most IGMP queries and responses are sent to a mcast address so the source address is irrelevant). If you think "boy Sean, who would be that stupid?" then consider that APNIC had to reserve
1.1.1.0/24 because so many people use 1.1.1.1 and so forth on their networks (guilty!).
I don't see any multicast traffic on my host, so maybe your router having it enabled is a test or a mistake. Shaw has lots of crap on their network... Look at your ARP traffic for example, you're probably getting many pps of ARP for stuff not even on your local subnet. It's been that way for at least 8 years.
Sean