Want to be really sure that your Internet of Things gadgets and laptops aren't being remotely controlled by malware?
Electrically isolating a device (including your router) from the internet is a very thorough way of disconnecting it, and you can do it in style with John Edgar Park and Sean Michael Ragan's "Internet Kill Switch."
If you want to be double-dog sure, here's a simple, fool-proof answer: a hardware kill switch. Put one on the wired connection between your computer and router and use it to unambiguously isolate that computer from the internet whenever you want. Or put it between your router (wireless or otherwise) and your ISP hardware to control the connection for the entire house. Sure, you could just unplug the cable, but that's hard on the connectors, and the switch is faster to use and neater-looking, to boot.
Build an Internet Kill Switch
[John Edgar Park and Sean Michael Ragan/Make]
(via Naked Capitalism)