On a rope, hang 10 socks with pegs, each with different items inside or soaked in a liquid to provide different smells.  Cubs to smell the socks and try to identify the different smells.  Ideas:

Cinnamon

Lemon/orange

Sanitizer

Curry/strong spice

Banana

Plant (e.g eucalyptus or lavender)

Deodorant/perfume

Vinegar

Garlic/onion

Apple or another fruit