So, you understand what that terrible Heartbleed bug's all about, but you can't really explain it in words even a five-year-old can understand. Here's what you should do when someone asks at your weekly family dinner, then: launch the XKCD website and show them its two recent Heartbleed strips. With just a bit more detail from your end, the webcomic should make the concept easy to grok, like what it did for global warming, radiation and Saturn V rockets in the past.