I first saw one of these up close at the vacation house we stayed at recently. It seemed to be geared towards grown up but even Big Boy was curious about it. Then recently, I saw a lot of online buzz about The Crafty Nest's nicely executed DIY versions.
Empty bottle - Vanessa uses a Voss bottle in her tutorial and I think she nailed it aesthetically. I had a terrible time sourcing the plastic version of the bottles locally but finally found some at the local Bristol Farms.
Tchotkes - anything non perishable and interesting that you can fit through the neck of the bottle. My button jar is a bit bare but I hit the motherlode online at the Sausalito Ferry Co. Other sources could include Etsy and Tiny Things Are Cute.
Filler - the tutorial uses popcorn but I am toying with using rice or orzo.
I will post photos once it is complete!