You just update the firmware on your xbox dvd-rom to the latest IXtreme firmware for your rom version. Its simple use JungleFlasher.
and then you can either download or copy the games you want to play
but you do run the risk of being caught and banned from XBLive.. they ban your mac address on your xbox not your account, its a perma ban.
google these terms and read alot
xbins
xboxscene
jungle flasher
and for irc help its irc.efnet.net channel #fw