doing things with my family (homeschooling, reading stories, arts & crafts, puzzles, board games, museums, art galleries, parks, etc.)
going to (or being in) a symphony/opera/ballet
"tabletop" role-playing games (I ran games at major conventions, back when that was big)
collecting books, or just browsing in bookstores
Magic the Gathering (we used to play in the tournaments; R and I love to play it after the kids go to bed)
walking (to keep fit)
bicycling (R and I did a bike trip around NY state as our honeymoon)
reading just about any topic, fiction or nonfiction; I am always reading at least 2 or 3 books at any given time
gardening & taking care of my houseplants (I call them "my babies")
history, anthropology, archeology, linguistics (I have a history degree and another in anthropology/linguistics)
learning & studying languages (I speak over 10 languages, not all of them fluently)
writing fiction and nonfiction
working on my constructed language (or "conlang" for those who know of such things)
movies (as a filmmaker, I have a keen interest in all films)
acting, directing, any aspect of stage/film
doing voice overs for commercials or animation
art (drawing, painting, sculpting, wood, clay, art films, performance art)
Pokemon (games, books, toys, etc.)
watching or discussing all my favorite TV series (Northern Exposure, Lost, Star Trek, Doctor Who, Babylon 5, Farscape, Heroes, etc.)
collecting Micronauts & other old toys
used to be into comic books, but that stuff is the crack!
"Whoa, a new Spider-Man title? I'm already collecting 4 of his titles, but I can add another..."
"A crossover with Batman? OK, I can buy double titles for a couple months..."
Practically needed a 12 step program to get out of that addiction!