Students watch two clips from the Lego Movie. I use the clip at the beginning (about 5 minutes in) where Emmett is saying good morning. It is a great review of the reflexive and getting ready in the morning vocabulary. I start the second clip when Emmett drives in his car, but you can decide when to start and stop the clips. I usually stop when Emmett gets to work. My students really like watching the movie and the activity really helps to show the differences between the two tenses.
To show the contrast of the two tenses, after the first clip, I ask students to write down ten things Emmett did using the preterit and then five sentences to describe the scene using the imperfect. They then write a brief description of the scene combining both the preterit and the imperfect.
For the second clip they do the opposite. They start by describing the scene using the imperfect and then write four things Emmett did using the preterit. Lastly, they write four sentences to practice simultaneous actions or an interrupted action based on what they saw in the clips.
Youtube addresses for the clips are given.