CSSPlus, or "Children's Sermon Service...Plus," boasts over 3,400 children's sermons (and activities) based on the Gospel and 2nd Reading of the lectionary. There are generally 12 to 14 different children's sermons and 5 to 6 activities for each Sunday from which to choose.
>> sample listing of children's sermons for a typical Sunday
>> sample Children's sermon
1-Year - $29.95