What is something fun for a 6month, 2year,3year, and a 5year old to do wile its cold and rainy outside? (other than to watch cartoons plz)

Crank up some kid-friendly tunes and dance!

Arts and graft day!!! Make something special for daddy for when he gets home, Or maybe some x-mass decorations.
Awesome question Lynn.

It wouldn't work for the 6 month old but it would for the others. Plant popcorn. Any uncooked kernels will do - even if from the microwave bag kind. They start growing really fast (you'll see sprouts in a couple days) and the growth is noticeable every day. I did this with my kids as well as my nieces and nephews when they were little and with it only taking a couple days (instead of a couple weeks) to see the fruits of their labor, they loved it.

Break out the finger paint, construction paper, crayon, markers and a few boxes. Spread an old sheet on the floor, and get down on the floor and let them create what they want. They make all of these things in non toxic kid save formula's so that all of them can participate. Have fun mom, it will be one of your best memories +4

Edit: Don't forget the elmers glue!

Candyland and Chutes & Ladders are a couple of great games.

Make a fort out of blankets from around the house.

Finger painting :D. My kids love it...maybe not for the 6 month old though lol.
My kids like to play with the stick of glue and paper. I cut things for them ( shapes-trees-fruit) and give them the construction paper and glue and they get creative.
Christmas decorations of course ;).
To make the paper snowflakes as you asked, just flod the paper in 4,6,8 folds and start cutting ;).
Have fun with the kids :D. Fortunately is nice out here today so I dont have to get creative lol.