I spent a bit of time looking around Flickr and the internet for some some ideas using my new carboy. Most of which were filled with wine and beer!
Seaglass via Green Wellies
Paper Stars via szeretlek_ma
Buttons and Spools via littlethings1
Monochromatic items via sunshinesyrie
Crafty Bits via One Good Bumblebee
Golf Tees via Apartment Therapy
I like the idea of thread spools, or something natural like twigs - maybe lit from inside?