Live plot of data published by Swissgrid (thanks!) on the frequency of the Continental European Power System (@entso_e). Here you can track how a Serbian/Kosovo conflict is making your oven clock show the wrong time.
If the frequency is above 50Hz, the cumulative "backlog" decreases, if below 50Hz, the cumulative difference is becoming bigger again. As long as the green line ('the fit') is going down, the situation on average is getting worse. An up to the second graph by Thomas Gobmaier can be found here.
Raw data is in freqlog, gnuplot script is here. Comments, remarks: @PowerDNS_Bert
Longer term graph: