Lets see......
Languages, Arsenal, coins, shiny rocks, arrowheads, Native American culture, cloud formations, astronomy, World War 2, Where's Waldo books, Firefly, Scrubs, Poland, computers, anime, manga, ancient civilizations, Chinese astrology, Indiana Jones, Star Wars, metal bottle caps, samurai, sharpie markers, stickers, The X-Files, Lord of the Rings, soccer, The Chronicles of Narnia, classical music, snow globes, dogs, refrigerator magnets, poetry, the English Premier League, Ireland International Soccer Team, X-Men, the World Cup, and RPG video games.
Everyone used to describe me as "unusually intense" when I was a kid. My uncle once bought me a shoe box full of fridge magnets and I didn't play with anything else for half a year. When I went to Mexico I compulsively collected metal bottle caps but everyone thought it was funny. My father once made the mistake of buying me a limited edition VHS-release of the original Star Wars trilogy. My mother hid it from me for three years. When the World Cup was in the US in 1994 I would sit in front of TV watching replays for hours without moving. I still do that actually.
I go from one obsession to the other fairly regularly but I never seem to lose any interest in any of them. I always seem to get back to them eventually.
Shiny rocks (well, geology in general) and dogs are among my obsessions as well. I am also interested in meteorology and architecture, and anything involving Central Asia (the 'Stans).