If you set your date to a flea market, dig up some fossils and take them to blathers and
get them checked. But don't let blathers have them!
Put them in your home and wait, someone will walk in you can sell the fossils for 10,000
each maybe even more depending on how rare they are!

You may have seen Phylis in the cafe before, but after 11pm you can find Harriet in there
as well!
During the day you may also found Rover, but you can also find Kappn who if you talk to
him enough he'll mention things from the original animal crossing!