Set process name

So i need a bit of help finding some code.
I'm looking for a code that can change a process name (the one you see in task manager), either while its running or before it starts - it doesn't matter. Bonus if you can show me how to hide the process from all programs.
code in: C++, C#, or VB.net appreciated. Anything else is fine, but it'll be a hassle.

A thread can be on topic and still be shitting up the board, the two are not mutually exclusive.