Kellar

Hello everyone, I don't really know if this is the right place,but here it goes. I just recently bought Halo 4 and I am willing to play MP however I have an XBox 360 slim with 4 Gigabytes of memory,do I need to buy a HD to play(I am not interested in recording movies and whatanot,just normal play),If not can I use a regular pen-drive to store this information,if yes what do I need to do to make the pendrive able to interact with the console(what Format?NTSC,FAT32,some special treatment?) Can I use a regular pendrive at all to store movies and foundry maps If I want? Thanks in Advance.