I was putting away laundry this morning and I left my drawer open for a minute. That's how long it took for my adorably naughty kitty Tyger to hop in and claim it as her special place. She's also famous for prying up the heat vent covers to get into our ventilation system. If she can find her way into anything, she can't resist it.
I have two cats, Lois and Guillermo. Neither is bright enough to pry up the heat registers, but I have found them in closed cabinets before. Regardless of whether it's intentional or someone has closed them in, they always give me the look, "I meant to do that."