Question block or activated block is a switchable powerup block(originally from Super Mario Bros.) where player can activate the effect of the block(typically dispensing a powerup or spawning some entity) by bumping the block with their head, jumping down or throwing some mobile object with block collision property towards the block.
Multiple activations of the block are possible as well as reset of block to original state.
Types of activation:
1.Bottom-up: Either due player jump towards the bottom of the block or mobile object is thrown in direction of block.
2.Side: usually reserved for thrown objects collision.
3.Top-down: Usually reserved for special moves such as ground slams and explosive objects.

1.Note block(same mechanic, additionally acts as spring)
2.Hidden block(invisible question block), can be moving invisibly.
3.Brick bonus block(where a normal brick/destructible acts as question block)
4.Vine block, spawn a vine on top.