I love coins and so do my kids. I think it is cool to hold a hundred year old coin in your hand,. My children get excited when they see a penny. Do you remember the time when you actually was happy when you found a penny?
Get a penny book, 1909-1940 or 1940-1958. These are all wheat pennies. Go to eBay and buy a lot of wheat pennies. When they come in the mail, go through them with your children. Take the pennies that fit into the book and help your children fill the books. Your children will get a kick out of this. Keep the books for your children and give them to them when they get older.
The cool thing with wheat pennies are they are pretty cheap and never lose their value. If you are lucky, you will find a valuable wheat penny. I actually found a 1931s one time in a roll of wheat pennies I bought for three dollars.
Having fun with wheat pennies is fun and is a hobby that can build a bond between you and your children. As you check out the coins, you can teach them a history lesson. You could look up some things that happened during some of the dates on the pennies.