Simple:
* My hobby is reading.
* Gardening is a relaxing hobby.
More descriptive:
* My favorite hobby is collecting vintage postcards, which allows me to explore different eras and cultures.
* He enjoys the challenge of woodworking, a hobby that requires both skill and patience.
In a conversation:
* "What are your hobbies?"
* "I'm trying to pick up a new hobby, any suggestions?"
In a formal setting:
* Her hobbies include painting and volunteering at the local animal shelter.
* His application highlighted his hobbies, which included chess and competitive swimming.
Remember to use the correct grammatical form of the word "hobby" based on the context of your sentence. For example, you can use "hobby" as a noun, a verb, or an adjective.