On pseudorandom numbers and Tetris

So I'm programming a Tetris clone in Sepples and SDL. I need a method of generating a random number between 0 and 6 (seven different types of blocks) that gives a, more or less, even chance for each value to occur. I could use ctime and cstdlib to generate a pseudorandom number, then modulus that number by 7, but that wouldn't be an even chance. Some pieces would fall more often than others.

How does /prog/ get their pseudorandoms to be convincing?

"Admitting to and then exploring that connection was the WHOLE POINT of the book! It never ceases to amaze me how people think they can kill me with ammunition I GIVE THEM. It's rather like when I allow people to punch me in my toned torso."

"It's rather like when I allow people to punch me in my toned torso."

"It's rather like when I allow people to punch me in my toned torso."

"It's rather like when I allow people to punch me in my toned torso."

http://www.mdickie.com/blog.htm