On sunday morning at half past four, two old tom cats came knocking on my door.
I opened the door to let them in - and they knocked me down with a rolling pin!
I googled "tom cats came knocking" and got about 1400 hits, including several different versions. All appeared to be one form of playground game or another. Perhaps, Lankeela, if you have a look at more of them than I did, you'll get a more definitive answer.