The students spent the first 50 minutes of class finishing up their mobile animal models. Since progress was so slow last class, we decided to change the curriculum slightly by bringing in an NXT car model and instructions. This turned out well, as most groups chose to use a combination of the instructions and their own design. By the end of 50 minutes all groups had a mobile model with their lego animal attached in some way.
The last ten minutes were spent giving a basic demonstration of the kind of work they'll be doing for their final project. We brought in a NXT car with touch and sound sensors that was programmed to move away whenever it heard a loud noise or bumped into another object. This design was intentionally poor in that it had to actually touch an obstacle before it knew to back up, and in that when it sensed a loud noise it moved away in a random direction. For the last 5 minutes before cleaning up we discussed the pros and cons of our animal behavioral model and (hopefully) got them thinking about how they should go about programming their own models.
Note: This classroom has already worked with NXT sensors as part of their fall STOMP curriculum so we didn't think it was necessary to dedicate a whole lesson to programming.