Instructables user dhouggy wanted to ride his bike indoors but didn't want to pay hundreds of dollars for a trainer or professionally-made roller. So with a couple 2x4s and some PVC pipe he was able to craft this working homemade model for just $50.
From the submitter:
So you have a ceiling fan in a room with a cathedral ceiling that needs a light bulb and no ladder available. Using a broom stick, an empty pill bottle, a hair scrunchy, a large chef's knife, and some duct tape you can build Bulb Changing Tool 5000. Simply cut a series 1-1/2" long slits lengthwise starting at the open end of the pill bottle to make a collapseable bulb holder. Wrap the hair scrunchy around the pill bottle to enable a nice grippy action. Punch a hole in the bottom of the pill bottle.