i have one cat in particular that will chew through any plastic bag in my kitchen, no doubt in the search for goodies. hamburger buns, cereal, cat treats, you name it. i have to buy plastic containers for everything just to keep my cat out of it.
he also knows that i keep cat treats in my desk drawer, so he will work at getting the drawer open to violate those treats. too bad they are locked safely away in a plastic tub. he tries, i guess.

My cat knows how to paw open then proceed to get inside a cupboard, but she can't get back out because she's so meak D:.
Your cat treat story is funny though, thanks for the share :).
My cat will chew through the side of the dry food bag if you leave it on the ground.
If he can't reach it, he will attempt to jump to where it is and knock it over.
I had a friend tell me of a dog they knew that figured out how to open the refrigerator, and once the dog's owner would leave the dog would go straight to the fridge and start dragging everything out of it! xD
The same dog honks the horn when left in the car until the owner comes back to the car! xD Funny dog
Catnip is the treat my little girl can sniff out of 3 different bags, in a container, in a closet, on the top shelf...How she gets it however is still a mystery to me. I gave up trying to save any for later. She always finds it...
Course this same little girl likes to chew empty cardboard boxes and the plastic bits off ANYTHING :D
Well, all of your cats managed to open food bags... mine opened a fresh bag of kitty litter (7kg, might I add! It's a big bag!) by tearing a neat horizontal hole near the top, climbing in, and leaving a nice steaming gift for his mama. Let it be noted that his kitty litter tray, which is always nice and clean and frequently emptied, was within 3m of this incident. -_-"
His main other trick that he only just discovered this week is to lie on top of the flatscreen tv (an accomplishment in itself considering his fat belly) and watch you as you watch tv. it's really unsettling to watch samantha from sex and the city getting her rocks off with some guy while your 6 month old kitten glares into your eyes accusingly from across the room...
my rabbits learnt to climb walls. they are escape artists.
they chewed the back of their cage, tried to dig their way out of the garden and once, i opened the front door to go for the bus, and one of my rabbits was on the doorstep. how he got there, i;ll never know, since he was round the back, which is fenced off with a gate.
srsly. my rabbits don't want to live here ):