In Grand Theft Auto 4, I always like to get a huge cache of weapons to wreak havoc on the city. You can get them on the XBox 360 and PS3 by doing the following:
1. Take out the cell phone.
2. Dial one of the following phone number codes.
486-555-0100 for the Baseball Bat, Handgun, Shotgun, MP5, M4, Sniper Rifle, RPG and Grenades.
486-555-0150 for the Knife, Molotovs, Handgun, Shotgun, Uzi, AK47, Sniper Rifle and RPG.