The popcorn smell at our local Wal mart always makes me think of those popcorn buckets at WDW! I love that popcorn, I will eat it even if I am full, and I can't stop eating it even after I get a stomach ache! Fair warning to everyone though, the WM popcorn tastes nothing like WDW popcorn.
Also, everyday I walk by a large outdoor fountain to get to my building. On certain days the smell of fountain/chlorine/and hot concrete reminds me of WDW.
Almost anything can remind me of WDW-- music, smells, sights, everything.