Cats are very intelligent animals. They can learn tricks quickly through trial and error. Don't let their attitude fool you. Cats are extremely trainable but they only do tricks on command if it's within their own interest. [See Can Cats be Trained?]
There are many things that cats can do by imitating their human companions such as opening windows, doors, jars or cupboard doors. Below are 4 videos that I find absolutely amazing. Look at those smart little furry babies effortlessly working things we humans do.
Studies have shown that cats have the intelligence that is equivalent to a 2 year old child. How incredible is that?
Enjoy the videos!