I jokingly posted this picture above on my instagram of an empty Jif container with a sloppy hole punched through and a straw. The thing is, I don't have sippy cups anymore! I found them to be disgusting (crevices full of spoiled drink!) and Wyatt usually just drinks out of regular cups, and only in the kitchen (at least I attempt to keep his drinks only in the kitchen). He asked super nicely if he could please have a drink in the living room and of course I said yes because he's cute. So I went looking for maybe some lone sippy cup that might have been hiding in the cabinet or something, but nothing. I resorted to a punched in hole in a peanut butter container and voila. Not really amazing or anything.
But, this idea could be so much nicer! I experimented with some glass jars with proper lids after posting the photo. I don't know how you feel about your kid with glass, but I'm generally okay with it. For me it's just keeping a drink contained and not dealing with gross crevices of a sippy cup. Of course, these cups are not spill proof, but they are splash proof, so that's good enough for me. Wyatt is older and he's not throwing his drinks on the floor anymore. You could do this with plastic peanut butter containers (or whatever), but I'd use a drill to make the hole since punching a hole through with a screw driver or hammer and nail will shatter it (look at my instagram picture for reference).
To punch my hole through my glass jar lids I just used a screw driver thick enough to fit in a straw. It worked fine, just took some muscle.
I also think this idea would be great at cook-outs and bbqs. It would keep the bugs out of your drinks!