The easiest birthday puzzle starts with a five-letter word tied to the person or the party: a name, nickname, hobby, favorite place, pet, snack, or inside joke. If the word is too obscure, use the host screen and hints to keep it playful.
Make the round social
Cast the host screen so everyone sees the leaderboard.
Have guests solve from their phones so answers stay private.
Use one short practice round if guests have mixed puzzle experience.
Follow with a custom round tied to the birthday person.
Good custom answers are personal enough to feel special and common enough that guests can solve them.
Add more than one puzzle
A custom Wordle-style round pairs well with a Connections-style board or mini crossword using the same theme. That gives puzzle people something to chase while casual guests still understand what is happening.
Host setup: create a lobby, choose or build a game, cast the host screen to a TV, and have guests join from their phones.