Hey, Moms, run out to Home Depot or Lowe's (maybe Walmart) and pick up an amaryllis bulb in boxes in the gardening section. Most are on clearance now but are perfect.
Let your kids watch the daily growth by measuring with a ruler and chart the growth. In four to six weeks they will be around 18 inches tall and will have a huge rewarding bulb. If you hurry it may bulb around Christmas.
It is amazing how quickly they grow. I have two in my kitchen window. One is 4.5 inches, the other 3 inches and I planted them Saturday.