This can be used for an introduction to Philosophy, Logic, or even a debate class. There is a two page handout that explains what a valid and sound argument are (includes an explanation of the two terms as well as examples). Pages 3, 4 and 5 are an individual student worksheet, in which the student will examine a handful of arguments and determine whether or not they are sound and/or valid. Page 6 is the answer key.
I find it most useful for students to use this material as follows: read the handout together as a group, slowly reviewing the content and checking for comprehension. Then, have students complete the worksheet independently either in class or as homework. Once everyone has completed the assignment, review the answers together. The discussion seems to help the students that weren't as quick to understand the concepts. At the end there is a bonus question for students to come up with their own arguments - you can have volunteers share their arguments on the board which is a fun activity.
This work is high school level difficulty, and in my experience seems to be enjoyable for students.