HTML, CSS, JavaScript, Python, and C++. In the process of learning C# (for Unity) and Java (for High School). I also learn different programming languages when I want to mess with people, lol. For pranks on you're friends, I suggest learning Visual Basic. It's amazing to mess with people!
Visual Basic is based on BASIC, which is well... a basic programming language. Python is amazing also, if you want to feel like you know something important learn python. Python can do anything, just slow. That's where C++ comes in; it can do almost (almost) everything python can but faster. And you responded to me at 12:00 XD.