(These official reports typically provide detailed information on Games, planning, operations, Olympic cultural-related activities, results and in most cases, they are also a rich source of Games photography)
Another one:
Contemporary art.
I am not an art collector or anything, but the art movements of the 20th and 21st centuries are my favourite. They seem to piss off many people, because they defy expectations of what art is supposed to be.
I am interested in Polish noun declension tables! This is an integral part of Polish grammar and is so much fun to deal with!
For example, the word for girl in Polish is dziewczyna. Depending on its position and grammatical function in the sentence, the noun should be used in nominative, genitive, dative, accusative, instrumental, locative and vocative cases. Nouns are in both singular and plural forms. I enjoy gazing at such declension tables, learn them by heart and practise Polish grammar! Most people, even Polish native speakers are not as interested as I am!
dziewczyna dziewczyny
dziewczyny dziewczyn
dziewczynie dziewczynom
dziewczynę, dziewczyny,
dziewczyną, dziewczynami
dziewczynie, dziewczynach,
dziewczyno, dziewczyny
