What makes a great learner activity? Well, it all depends on what your goals of the activity are. Learner activities are similar to exams, in that you don't want to start off with the most difficult question. This can leave students discouraged and may prevent them from even continuing with the rest of their exam. For a learner activity you should begin with simpler tasks, then move onto more complex tasks in order to prevent students from becoming discouraged. This also ensures that they have the necessary foundations before moving on with an activity.
Another great strategy to use for learner activities is to have different paths available within the activities to achieve the learning objectives. One method our text talks about is giving a pretest to sort students out who may need a remedial activity before beginning the activity, and then an enrichment activity at the end for those students who finish early. These of course, can become more and more complex, as you add in multiple paths between in achieving the learning objectives, and may be based on student interest or learning styles.
The curriculum webs textbook also goes into a lengthy list of different criteria for selecting activities, but the one I felt really hit home for math class was to make sure that the activity is authentic. If it is tying in real life applications of the math, and modeling things that actually occur in the "real world" then these tasks become more meaningful for students. They also form a connection for students and make what they are doing in school relevant for their lives. For instance, rather than simply having students practice writing out numbers in words, have them practice writing the numbers on the appropriate line on a check.
I'm still working on filtering some of these websites, but as parent teacher conferences are tomorrow and it's almost midnight this will have to do until I can come back and edit...enjoy!