This is an easy enough cognitive or receptive language activity. Sometimes though the simple escapes us as therapists as we try to create.
I give students their own white boards with their categories already on them or just three lines. This depends on the skill level of students. Then I give them three cards in three different categories. Obviously, the number of cards and categories can vary for differentiation purposes. Then the students figure out which category the various cards belong to. The EASY part I added (that the students LOVE...) is that once they feel like they have them all done they get to ring the bell. I KNOW! The first one to ring the bell AND get them all right is the winner of the point.
I DO LOVE A GOOD BELL! Now I have two of them on my speech table that ring a different tone. I drive the mainstream teachers a little crazy, but I figure that is all a part of my job!