Scented markers -- Art class in elementary school and lime, lemon, orange, and grape scented markers. Yep, there's nothing like encouraging kids under twelve to inhale marker fumes by making them smell like fruit.
Super Hold Aqua Net - Last summer I was getting ready for a wedding, and I realized I was out of hair spray. I had Matt pick me up some, and he comes back with aqua net! I cracked up laughing, but my hair stayed put all night.
A freshly opened box of Crayola crayons. I love that smell. I remember the jumbo ones my mom bought me and I remember my first 64 box that my grandma bought me after I had my tonsils out in Kindergarten!