If your friend pulled a knife on you...

[poyoscorp]

If they weren't that good a friend, I would step towards them and to the side, then I would grab the wrist of the knife hand and pull myself in to knee them in the gut. Then while they are bunched over in pain, I will take the knife away. Pretty badass right?

[Popo]

Well, depends on the friend..
One of my friends has actually planned to do such a thing (halloween, acting as the joker, dull knife, you get the idea), so I'd just laugh, unless it was a sharp knife.
Then, I'd get nervous, and likely do something extremely stupid.
As for most of my other friends, Read the above statement.

[TrianglePointPen]

I'd flex my abs of steel and charge them

[itsmefcours]

i haz no friends to hold a knife or run from. apart from this one guys. but he rapes me so...

[Borntorule]

I'd probably just freeze for a sec or two and then do a jump/tackle into them take the knife and beat the living (and dead) crap out of em.

[Peacefrog]

Ctrl+Alt+Delete>Task manager>Select friend/s>End Process>Have Cake