What activities do you do to engage your 3-month-old baby?

I sang songs to him - nursery rhymes mostly. I also did a few baby exercises like cycling his legs, putting his hands above his head, crossing his legs etc which he loved. I was advised to keep talking to him so that he learns words. I did try but it's quite hard to talk non stop to someone who doesn't answer back. My son at 1 is quite chatty now so perhaps it helped! A lot of parents will start flash cards with their kids early on as well.