When troubleshooting multicast problem I find myself checking if IGMP snooping works as intended. "show mac address-table multicast" on Cisco switches shows MAC addresses of multicast groups. Tired of converting Multicast IPs into MACs with pencil and paper, I wrote my first ever script in Python which does just that. It takes IP address of multicast group as a parameter. Although I did some testing there might be bugs, so beware.
See Cisco's white paper for explanation how the conversion is done.