You can fit up to 4300 Mb worth ( the question you asked is really how much time fits in a 1 quart bottle)
well i mean i know how much size wise but amount wise. so far i managed to put 10 on 1 dvd trying to go for 12 but not sure
A little more information would be nice - the size of the episodes you're trying to put on a DVD, for one. Bear in mind that when you transcode avi to dvd compliant files, you are uncompressing the video data and it's going to take up more space on your dvd than it does on your HDD. You can compress it to fit more on to a DVD, but this lowers video quality in the final product.