I used this one year in one of our home schooling classes. It is aimed at an adult audience and sometimes needed to be filtered through a reformed lens. But it's a good way to get an overview of church history and to discuss something of the early martyrs, councils, and heresy. With 100, you could do one a week or combine a few smaller entries into one week, giving yourself more time on the notables.
[ame=http://www.amazon.com/Most-Important-Events-Christian-History/dp/0800756444/ref=sr_1_2?ie=UTF8&s=books&qid=1253717639&sr=8-2#reader]Amazon.com: 100 Most Important Events in Christian History, The (9780800756444): A. Kenneth Curtis, J. Stephen Lang, Randy Petersen: Books[/ame]