How do i control things using my cell phone?

I know that is a very broad question so let me be more specific. Is there a way to hack into electronic devices such as phones, laptops, and TVs using my cell phone? For example i was watching iron man 2 and one scene he uses a little transparent pad he had in his pocket to take control over two flat screen TVs. I am aware that the technology in that movie is completely insane and we have nothing like it. But is there anyway i could do that on my phone. Get into my friends phone without them knowing, controlling my laptop, etc... Please only answer the question do not post smart allic remarks.