Crafts- there are plenty of ready-made kits and lots of ideas online using common items found in your home. Keep plastic table clothes handy to spread across table for easy clean up.
Bake- making homemade cookies or a cake together. Kids love mixing the ingredients and everyone loves to sample when it is done.
Dance party- turn up the music and dance. Be silly and have fun!
Music- make instruments using household items, form a band and make up a song.
Living room fort- use blankets and pillows and your living room furniture to build a fort.
Household obstacle course- use furniture and larger items to make an obstacle course in your home. It is a great way for the kids to burn energy.
Tell stories- start telling a story, and then hand it off to another member of the family to add to it. See how fun of a story you can invent as a family.
Read stories- it’s traditional, but still a favorite. Read a story to you children or better yet, have them read to you.
Hide and seek- again, traditional, but fun for everyone. Take turns being the seeker and make it fun for everyone.
Board games & card games- there are so many out there that are fun for the whole family. Play a round of each family member’s favorite game. Clue and UNO are very popular ones in our home.
Watch a movie- when you need some time to unwind, make some popcorn, and snuggle under a blanket and watch a family friendly movie together.
Take a rain walk- every put on their rain coats and boots, grab your favorite umbrella and take a family walk. No one will melt in the rain. Jump in every puddle you see!
Hopefully that is enough ideas to get you started!