* ¿Cómo estás? (pronounced koh-moh es-TAHS): This is a more formal way to ask someone about their general state of being.
* ¿Qué haces? (pronounced keh AH-cehs): This translates literally to "What are you doing?" but it can also be used to mean "What's up?" in a casual context.
* ¿Qué hay? (pronounced keh i): This is a less common way to say "What's up?" but it is still used in some parts of the Spanish-speaking world.
* ¿Qué onda? (pronounced keh OHN-dah): This is a slang term that is often used in Mexico to mean "What's up?"
The appropriate way to say "What's up?" in Spanish will depend on the formality of the situation and the region of the Spanish-speaking world where you are.