So domestic cats are supposed to be crepuscular, i.e. not particularly nocturnal especially house cats. My pair have tended to follow this - active around getting up time and in the evenings mostly then zonked out in the middle of the day & at night. The last activity of the day would be the zoomies around 5-10 minutes after lights out then silence until I start to move in the morning (with a couple of very rare exceptions).
Suddenly the last few days they have decided that during the night is the best time to go tearing round killing each other & the toy mice. Every single night I'm being woken by galloping noises, occasional quiet yowling (they don't do loud), thumping, and even being landed on as they bounce over the bed rather than under it. At least 2-3 times every night this is happening, and I keep treading on toy mice as I get out of bed (mostly brought from downstairs). Mad zoomies goes on until a little while after breakfast until they finally settle down.
In one way I'm really happy that they are happy and confident enough to do this, in another I'm bloody tired as I can't just sleep in as Boycat has very definite ideas on the latest I should get up & he's hard to ignore. Most puzzling is where all this extra energy is coming from, as they haven't reduced their other activities at all.