pregnancy annocment ideas

Winter

so i have two boys full time (ages 2 and 5) and every other weekend my stepsons come over (ages 8 and 10) i really want to involve all 4 boys in announcing the newest baby but i need ideas how to. i dont find out my due date till the 21st of this month and i dont have tons of money to buy stuff so cheap ideas would be awesome. thanks in advance ladies