I love easy DIY's and this one certainly qualifies. All you need is a bottle and some spray on chalkboard paint and you're done. I would recommend using Krylon chalkboard paint as I have had good results with this brand (this is not a sponsored post but simply my own observation).
Choose a bottle.
Remove the label from the bottle using hot water (if there is one).
Dry the bottle and make sure it is completely dry before spray painting.
Spray the chalkboard paint onto the bottle following the directions on the can.
Let dry 24 hours.
Use chalk to draw or write what you like on the bottle.