I don't think I've ever had this problem in the past, but maybe it was because I always had a bi-weekly cleaning woman and a babysitter coming regularly who were secretly cleaning it?
Anyway, both of my kitchen drains smell and seem moldy on a regular basis. I've tried pouring vinegar & baking soda down both sides and letting it sit, spraying Tilex with bleach, and scrubbing w/ soap & water, but the mold and small always seem to be there. It's especially true on the side with the garbage disposal with those rubber flaps. This is gross, but every time I make pasta for my kids and drain it over that side of the sink, as the boiling water goes down the drain I instantly smell mold coming up from the sink (and I imagine, "infecting" the innocent pasta sitting there in the colander).
So what's your regular kitchen sink maintenance to avoid this kind of thing? Do you scrub daily and if so, with what? Any other regular maintenance?