First of all, use g_debugmelee 1, then give yourself fists by give weaponnum 14
Then before you attack, use forcespeed and do a unarmed special (aka for choke, back+attack+alt), preferabbly the judo throw, because it's the funniest. Now when force speed runs out, the animation will play by itself! It's like an invisible hand playing around with the npc!:D
that's not interesting in the least.
You can do that in the full version too. I only did it in the demo though.
It's actually quite interesting and cool, but it's already been posted in the "Not Enough Customization.." threads. ; )