There's so much you can do with packing tape (besides packing). You can use it to seal art designs, turn everyday objects into sculptures, and even transfer photos. Or, if you have some index cards, you can turn them into a DIY dry-erase board that folds up and fits in your pocket like Redditor robertgfthomas did.
It's super easy—just lay the index cards out in rows, cover them in packing tape, then turn them over and do the same on the other side. Trim the edges with a pair of scissors, then you're all set.
Don't have any packing tape? Check out robertgfthomas's instructions to find out how to do this with contact paper. Or, if you're too lazy to make one, he's also selling them on his website for five bucks.