Split Screen
The split screen USB hack for "Modern Warfare 2" allows you to drastically alter the offline split screen version of the game. With this hack, you can unlock all weapons, custom class slots, titles, emblems, attachments and instantly become level 70 with tenth prestige. You can do some other outlandish modifications besides just unlocking everything though. You can put a perk into an attachment slot. You can take a weapon, and put it on as an attachment to a different weapon, which isn't even logistically possible. You can also change how many kills it takes to earn a kill streak.
Campaign
The USB campaign hack for "Modern Warfare 2" allows you to take a saved game from your campaign, and alter the way the game works. You can make a lot of changes that you'd be able to make with the developer tools enabled on the PC version of MW2. Some of the changes you can make include infinite health, infinite ammo, unlimited sprint, adjust the sprint speed, adjust field of vision and alter the heads-up display.
Gamertag
The gamertag hack isn't specifically for "Modern Warfare 2." However, it will show up when playing MW2, and if you've spent any time playing the game online, you've probably seen a few modded gamertags. The gamertag hack simply allows you to create one or many new gamertags that you can use on Xbox Live. You can even change the color of your gamertag. This is hack is mostly safe, but you can get banned from Xbox Live for doing it.
Modio
There are various tools needed for performing USB hacks, and most tools aren't needed for every hack. However, there is one tool that's needed for any USB hack you perform on your console: Modio. Modio is the primary tool for hacking and modding any console game, not just "Modern Warfare 2." Modio also provides a database of user-submitted, downloadable game saves, so you don't have to mod the game yourself. This database can save you a considerable amount of time that you'd spent modding yourself.