Here are two more activities that I have tried in class recently.
Linear Inequality TIC-TAC-TOE:
I borrowed this activity from @MathBerts and adjusted the directions to make it work in my classroom. Since I teach in a hybrid/station based classroom, students need to be able to complete their assignments without a teacher leading the activity. Most of my students enjoyed the activity. I had just one problem in that I had small groups of kids all using the same game board. I would recommend possibly copying each board on a different color of paper to alleviate this issue.
Domain and Range Go Fish:
This activity is a real winner. The kids LOVED it. I can't explain it, but every time we play go fish, they go nuts (in a good, on task, highly engaged sort of way). Shockingly, the first time we play Go Fish, I have to do a mini-lesson on how to play. Kids can be so deprived these days :( This activity really helped my kids to solidify their understanding of interval notation.