To watch the network activity associated with Redis using the popular tool Wireshark (formerly Ethereal).
To use this, copy redis-wireshark.lua to any filename you like under ~/.wireshark/plugins/. Then when you run Wireshark it will understand TCP communications on port 6379 as Redis messages, and will know how to interpret them. It also works with the command-line program tshark.
Depending on your system configuration, you may need to be root to capture live traffic. Since running plugins as root is not necessarily a great idea, try capturing some data to a PCAP file, then load it with the plugin after running Wireshark as an unprivileged user.