How are you doing?
How's it going?
How are you getting along these days?
What's going on?
How was your day?
How was the meeting/class/test?
Good/Great/Fantastic/Awesome/Not bad/Terrific/can't complain/no complaints.
Not much/Nothing much
I'm kind of busy/tired/bored/sick/upset.
It's been a good/tough day.
A: Hi, Dan, what's going on?
B: Not much.
A: How did the test go?
B: Awful, I don't even want to talk about it.
A: Hi, Bob. How was your weekend?
B: Terrible. I spent most of it at the office. How about you?
A: Hi, Stephen, did you go to the party last night?
B: Nah. I got stuck working late. How about you? Did you have time to go?