Pregnancy reveal ideas help!

I think I need to break the news to my four kids because they are not getting that mommy feels like death all of a sudden. They are 11,9,7,4 so they understand well. I was thinking a Christmas present reveal but I'm not sure what to put in it? Any ideas ladies? This will be a shocker for them as we all thought the 4th was the last but God has other plans and so we are blessed again.