Part of your Bar Mitzvah planning will be the choice of invitation. For the service itself, most families choose a formal or understated invitation. NOT USUALLY SEPARATE For the party, you can incorporate your child’s interests. Sports themed Bar Mitzvahs are very popular, but the theme can be anything. Today’s printers are used to working with parents in the midst of their Bar Mitzvah planning and are accustomed to helping with ideas for a theme.