Carry a pad and pencil and do sketches of strangers.

Walk or take public transport in random directions.

Put a chair outside and spend all day there.

Sleep on the balcony.

Draw graffiti.

Experiment with clothes, hair color, face paint.

Work out outdoors.

Tell people funny lies.

Go hungry just to feel hungry.

Bake cookies and give them away.

Talk to people nonverbally and see how much you can express.

Modify/deface objects to make them look funnier.