I like to teach as often as I can with tasks. My favorite site to go to for tasks is the Mathematics Vision Project (http://www.mathematicsvisionproject.org/).
This site is free and they have the teachers notes and homework included.
In my teaching with tasks, I have found that my students got tired of getting handouts to work on, and were less inclined to take notes when given a handout. So I started putting the tasks on slides. These first three sets are free so that you can get a feel for what they include and because the first three have a little less information on them than the others.
Most of the time the slides have the questions or ideas from the task to lead discussion, but they also include other things that I found helpful and interesting for my students. I also include detailed notes on how to present the material.
This PowerPoint presentation is for MVP Sec 2 Module 5 Task 1. You can view this task on their site. It includes a fun video to help students understand the concepts of proof. It also includes a page you can print and cut out for an activity in the lesson.