Apply force to a specific point on a rigid body

In unity I have a rigid body object and would like to apply force to a specific point. For example say I had a cube, I want to hit just the top right corner so it spins as a result. One idea I had considered is spawn a small sphere and fire it at it, then destroy the sphere. But is there a way to just apply the force?

• It's easier for us if you specify the engine in more than just the tag. And what have you tried? – Almo Dec 19 '12 at 21:57
• The first words are the engine I'm using, and the ball thing was all I had tried, and for the record throwing a ball of considerable mass (like a cannon ball) at a ragdoll is incridbly fun – ProtoJazz Dec 20 '12 at 2:40
• Woops! Somehow I missed the "in unity" part. I just started at "I have a rigid body" for some reason! :) – Almo Dec 20 '12 at 13:20

void ApplyForce(Rigidbody body) {