This is a worksheet I made for a class that was practicing "best" and "worst" in January.
I explain the same way I do with a lot of other activities, which is by demonstrating it with the JTE first. It helps to decide ahead of time which grammar point you're going to use for the answer. If the students have learned gerund form, that's how I like to answer. For example:
Once the students understand the general idea of the activity, I pass out the worksheet. As always, it helps to present a lot of examples to help the students think of ideas. Once everyone's thought of their ideas, I have the students survey each other about their opinions. Finally, the students need to choose the best and worst three from their classmates' answers, and write sentences that compare and rank them in order.
You can adapt the worksheet to spring or summer vacation as well, but be sure and change the text on the page and the images!