It's nice to sit outside on a sunny day and have a cold drink, but outdoor chairs often don't come with cup holders. Instructables user lime3D shows us a simple way to add cup holders to plastic furniture using repurposed cake icing containers.
You'll need 500g icing containers (or something of a similar shape), a marker, a drill and a jigsaw to add the cup holders. The process is as easy as tracing the bottom of the container and then cutting it out with the jigsaw. When you're done, slide the container into the hole. The instructions are specifically for adding cup holders to an Adirandack-style chair (like this), but it could easily be applied to pretty much any piece of plastic outdoor furniture with a wide arm rest. Head over to Instructables for the full guide.
Add Cup Holders to your Resin Adirondack Chair [Instructables]