Bottle cutters, DIY, could be pretty fun. The arcticle is from Plastolux, you’ll find the link at bottom of article. Picking up a Ephrems Old Time Bottle Cutting Kit on eBay, have a look at the awesome result.
The directions that comes with the kit are pretty strait forward. While making your score on the glass roll the bottle towards you and only go around once. If you go over your score a second time you may make pathways for the glass to run during the heating and cooling processes.
Get the details by visting Plastolux (thank you for the tip!)
Info/pictures: via Plastolux