Scarface: Say hello to my little friend!

Social networking Tony Montana style starts 160 minutes in, with an M203 grenade in the face. Admittedly it's a dodgy prop, that's mistakenly shown falling apart several times in the space of a couple of minutes on screen, but whatever: It's a great scene.

And if you have a bit more than twenty bucks to splash around, you could always buy the original if it's still for sale.