I modeled our Lenten calendar after the wonderful printable found over at Catholic Icing, with only a few minor artistic changes:
As simple as it is to color in one square per day, my 3.5 daughter absolutely loves it. It is one of the first things she wants to do each day!
The Lenten tradition of having a "sacrifices and good deeds" activity can be found all over the internet in various forms. This is what I decided to try this year:
Every time the children do something thoughtful, kind, or without complaining/whining, I add beans to the jar. (I have been generous with the beans -- my children are very little, after all!) On Easter I plan on replacing all the beans with a very special candy of some sort: a tangible representation of how Jesus takes all our measly efforts, which are literally "worth beans," and with His grace and merits transforms them into something very sweet and lovely indeed!