Let's imagine your house combi-boiler (this is what they're called in the UK) is linked to your home internet. Then, you actually had access to its data, namely, how much water is currently being pumped through due to the load-request from the taps!
Water Load Gauge
Hit the switch to turn on the water!
By using a little d3.js and an additional community plugin, this brilliant little visualization can be achieved.
For reference, the JS used to produce this visualization are found in the following links -
And credit to prakash27dec for the toggle switch snippet which can be found here -
prakash27dec toggle switch