Ответ:

A — 6 (Delicious food): the text describes National Donut Day and free donuts.

B — 5 (Feathers fly high): participants take part in a giant pillow fight.

C — 2 (The most colourful event): Holi is celebrated with colourful powders and water.

D — 1 (Baby jumping): El Colacho involves a man jumping over babies.

E — 3 (The messy festival): the Boryeong Mud Festival is based on mud-related activities.

Extra title: 4 (The Lego competition).