playground(s), beach(es), help in the yard (rake--or just jump in!-- the leaves, pull weeds), create art (crayons/markers; chalk on the driveway/sidewalk; collage with old magazines/newspapers/junk mail, scissors and paste), make homemade birthday cards for friends/ & relatives; play dress-up/role play; ball game(s) such as kickball, street hockey.

Make no-bake cookies/pancakes/waffles/French toast or homemade yeast bread (rising & punchdown are fun for kids); make homemade butter from heavy cream; go to a you-pick orchard/farm; make an early jack-o-lantern or do other fall decorating with leaves/gourds/whatever you have.

Teach them something new--a board game or physical game, household task like setting/clearing the table, dusting, sweeping, loading the washer or dryer. My mother used to have us clean out cabinets and closets on school vacations.

Put the triplets in a warm, sudsy tub to play; go through family photos and tell stories about everyone--let them make up stories, too. Story hour at the library or book store, my Barnes & Noble has a track for running cars/trucks/trains that 5-year-olds might enjoy (smaller toy stores sometimes have things out for kids to play with, too). Watch a video they haven't seen lately or borrow a new one from the llibrary.

Take a walk and try to identify whatever you see & hear--plants, birds, kinds of dogs & cats. Invite a couple of friends over to play.

Watch you fix something, maybe hand you the tools you need.

Have them read to you. Start reading a chapter book to them so you can read a couple of chapters a day through the whole vacation.

Places that hold music, art, and gym classes for children often have a free week between terms so people can try them out.