I love me some NFL Network. I actually watch the televised Combine results. You start to get desensitized to precisely how god-damned fast these guys are.
Check out this clip of the host, Rich Eisen, running the 40 yard dash. Watch it till the end and they'll superimpose Rich's performance against other incoming rookies and you'll see precisely how much faster these guys are from "normal" humans. It's insane.
http://www.youtube.com/watch?v=fZb3DRt6_Gk
J