If you don't want to play in the rain, which is a whole lot of fun and only available when it rains, here are some things we did:
1. Build a fort with blankets, sofa cushion, and pillows. Then, have a picnic inside of it.
2. Play hide-and-seek.
3. Bake something together. The oven keeps the house warm!
4. Call grandma on the phone or, if she's tech savvy, Skype her.
5. Have the kids prepare a skit, dance or karaoke song and let the rest of the family be the appreciative audience! Tell the older kids to upload to Youtube.
6. Have the older kids plan out a scavenger hunt for the littler ones. Make it easy for them to follow. Or, just hide old plastic Easter eggs around the house for them to find. Fill with pennies, etc.
7. Teach the kids to conduct a science experiment.
8. Go fishing. Attach yarn or string to a pole or yardstick. Use a clothespin at the end. Have them draw, color and cut out fish and worms. Clip a worm on the end of the string. Toss the line over a blanket strung across the room. Have the older ones, take the worm off and clip on a small treat. Let the fisher "reel in" his prize.
9. Put all the sofa cushions on the floor. Let them practice "gymnastics" by doing forward and backward rolls. Fun exercise!
10. Play indoor tag.
11. Blow up a balloon. Have everyone sit or lie down in the living room on two sides. Play volleyball with only your feet.