TOU pricing is pretty widespread at this point; I have it in a medium-sized city in Canada, and intentionally run laundry (electric dryer) in the evening when power is half the cost of daytime use. With EVs coming online and being set up to charge at night, it would definitely be nice to have a minute by minute spot pricing scheme, though, then you'd basically have a mechanism for using the chargers and other intelligent devices on the consumption side as an intelligent buffer.
It's goofy, but another one is situations where you have a lot of stored heat energy, thinking like pools, hot tubs, hot water heaters, etc— all those things could be activated in response to spot pricing with pretty simple policies (I want a shower of at least X degrees at 7am, I want the hot tub at at least Y degrees by 9pm, etc).