If we're talking about light guns as shadowzero suggests I would say the
Famicom light gun.
Type 99 Light Machine Gun - Red Orchestra 2: Rising Storm
A Japanese machine gun equip with x2.5 scope, bipod and bayonet. Everything you need to kill the American piggu
STG 44 - Day of Defeat
Classic assault rifle. It's 30 round magazine gave it distinct advantages over the other weapons in the game.
Rocket Launcher - Unreal series
With its relatively slow projectile, it was always gratifying to make that perfect long range shot onto a moving target.
Crossbow - Half-Life 2
Makeshift crossbow that fires super heated rebar. It was great fun in multiplayer where you can somewhat bounce the bolt of surfaces and pin people to walls.