Depends on the night :p tonight I'm finding my joy in laying very still and drinking water very slowly .... Last night I found my joy at the bottom of a bottle of tequila .... Then I vomited in my purse :/ there's no joy in my purse today :(
HMm tough question.. one I wish i had a super-cool witty answer to... but I don't.... I guess it would depend on what makes you happy.. What makes me happy and full of joy may not make you happy.. I am pretty happy right now.. to me joy is a nice warm kittty cat flopped on my lap.. and another nearby.. so joy to me is a nice warm kitty..
Sometimes joy is something else.. .when my daughter says something sweet, or she has a good day at school and does something cool, when she stands up for herself against all odds...
A garden full of plants or if I wanted to simplify and put it, literally into a cup - then a voucher/coupon/check for a garden centre so i can go buy loads and loads of plants - that would be a cup of joy to me :)