Free Online Family Tree Maker?

Does anyone know of any websites that allow you to make a family tree for free? I have tried ancestryplus and family tree maker but either you have to pay for it or it doesn't allow you to include a detailed tree (like including siblings).

This is the stupid assignment that my pastor has given FI and I to do for our second meeting with him tomorrow (I know I waited until the last minute).

Why couldn't he just ask us relationship questions like other pastors/priests do?