The first time I remember using a knife in a video game was in Wolfenstein 3D (1992) where a knife is the default weapon if you run out of ammo for your guns. Lots of first-person shooter games include a knife as a melee weapon. Pictured is a 1:1 paper model of the combat knife from Fallout 3 (2008). This model was created by Broken Papercrafts. The Pepakura PDO template for the papercraft may be downloaded here. The style of the Fallout combat knife is reminiscent of a Bowie fighting knife which was designed in the US in the early 19th century.

In the Fallout 3 video game, players can create an explosive device from found objects which include a lunchbox and bottle caps. This full size paper model of the so-called "bottlecap mine" was crafted with meticulous care by Broken Papercrafts. The illusion of the papercraft mine being real is enhanced by coloring the edges of the card stock and the addition of some bits of wire here and there. The Pepakura PDO files for the project may be downloaded here.

Other Papercraft Video Game Weapons:

Half-Life 1 Glock
KH2 Dream Sword
LoL Kennen Shuriken
Morrowind Daedric Dagger
Assorted Crossfire Weapons