Dumb question, since it has been asked plenty of times.
I want to back up my games onto disks so I can reinstall em later when I'm not playing them. How would I do this? And how would I do this for big games like Far Cry and UT2k4?
Thanks.
(And can you put it in layman's terms since I haven't slept in awhile and can't concentrate long enough to put many things together.)

Not sure what you want, which game ? GoG games ?
If it's GoG games you just need to burn the installer files unto a DVD/CD then you will be able to install them from the DVD-R any time you want without problem.
I don't think there are any GoG games which is bigger than a single DVD-R but even if that was the case the installer are splitted in 2Gb files so you could easily burn it on two disk if needed.

Let's take Advent Rising as an example. The installer files are:
setup_advent_rising.exe
setup_advent_rising-1.bin
setup_advent_rising-2.bin
setup_advent_rising-3.bin
To backup this game and later on install it from a DVD you'd need to burn all 4 files on the DVD.

I'd advice you to use external hard drive instead, preferably one of the mobile ones (that take power thru usb port) like I am doing. Much easier and convenient than trying to find what disk I burned what game later. I've pretty much backed everything up from game installers to extras. This includes both GOG and Gamergate games. You also save space.

If the files are too big to fit on one DVD (this shouldn't be a problem with GOGs or Steam backups) then use 7zip to archive them into DVD sized files. With games this can result in a slightly larger overall file size, but it's still the best way of going about it and is useful for games bought through EA Store, Gamersgate or Impulse.