Casual and Friendly:
* "Not much, just chillin'. What about you?" (Classic and versatile)
* "Just hangin' out. You?" (Short and sweet)
* "Same old, same old. You got anything exciting going on?" (Shows interest)
* "Hey! What's up with you?" (Flipping the question back)
* "Alright, what's new?" (Informal and direct)
Humorous:
* "Just avoiding my responsibilities. What about you?" (Self-deprecating)
* "Trying to survive another day. You?" (Sarcastic)
* "Same stuff, different day. You?" (Playful)
* "I'm on a quest for coffee. What's your mission?" (Lighthearted)
More Formal:
* "Not much, how about you?" (Simple and polite)
* "Just working/studying/etc. What are you up to?" (Professional)
* "Good, thanks for asking. What's going on with you?" (Formal and friendly)
Remember to consider:
* The person asking: Are they a close friend, acquaintance, or stranger?
* The setting: Is it a casual conversation or a more formal setting?
* Your own mood: Do you want to be playful, serious, or just friendly?
The best answer will depend on the situation, but these options should give you a good starting point!