Play dominoes with students while they discover the sugar-phosphate backbone and how the nitrogen bases attach to the deoxyribose. Or how adenine normally binds to thymine.
Also, if you only have one color, you can delete the numbers and letters that are flush with the dominoes.
How do you play? I am thinking about the number of tally marks on the domino is what you get. Students work in small groups with a complete set (38 with 6 pairs of nitrogen bases). Maybe give each player 8 to start and they have to draw if they can't play... just like regular dominoes. I will update this once I get things printed and try them out.
Did you try it? How did it go with the students in class? Let me know how to improve it if you have a great idea.