Now someone can correct me if I am wrong, I did some reading on corn recently and found that MOST varieties of sweet corn are hybrid. I believe the Serendipity sweet corn you speak of is an synergistic hybrid and won't grow true to the mother plant if you save if from your previously grown seed.
You should definitely do a search for a sweet corn with an open pollination if you plan to save your own seed for corn each year. Then allow the cobs to dry on the plant and collect when the seeds on the cobs are shrived and hard.
I tried to find some non-hybrid corn while I was out shopping the other day. There was no sweet corn that wasn't a hybrid. Instead I got some "ornamental" corn and I will use it for critter food. I only got the corn because I want to try the three sisters garden in one of my beds and needed something for the beans to climb
I have a golden bantam sweet corn that is open pollinated. You can find it online, its smaller ear like 6", but they mature in about 65 days. Definitely something to look into.
Golden bantam and shoepeg ("Country Gentleman") are the only widely-available OP nonhybrid sweet corns, and even those, you are not gonna find at the neighborhood garden center, you have to mail order.
There are a few other OP sweet corn varieites available through seed saver type outlets.
Bear in mind that there is a reason that old-timey "boil up yer sweet corn to eat" recipes have you boil them in *sugared* water -- they taste (IMHO) like rehydrated dried corn or cheap canned corn, not comparable to the hybrids we are used to today. I still like them, they have a nice corn-y taste, but they are "sweet" only in comparison to field corn
Vfem is right, hybrid corn won't hold true - as a matter of fact it generally won't produce anything except for nubs. Most of what we're used to as sweet corn today is hybrid. Older open pollinated varieties aren't as sweet.