I primarily mean for "experiences" to be a placeholder that includes movies, games, books, comics, tv shows, etc. and am interested in what made the geeky thing awesome in and of itself. However, feel free to include experiences that were your best, but maybe not because of the geeky thing itself. (Perhaps instead because of the person or circumstances connected to your experience of it.)
My top three would probably be:
1. The 24 hr Extra-Life Marathon (until the last 6 hours anyway)
Because as it turns out I own some great games that I haven't played in a long time, and NEVER have that kind of time to play in a single stretch. Awesome!!!
2. Playing Bioshock for the first time
Because I enjoy the intensity of real-time action games but horribly suck at them. This game allowed me to explore and experience a dark, fascinating world, loot and upgrade RPG style, and shoot bad guys without dying and having to play the same part of a game over and over and over and over and over... Great fun!
3. Watching all of Breaking Bad for the first time (not technically geek fiction, but clearly designed by a geek and in many ways FOR a geek audience.)
Because it was a character driven story that injected psychological realism, went to intense and dramatic places and kept me not just caring, but nearly agonizing over the outcome of these characters' lives. It had vigilantism, secret identities, cool gadgets and great villains... all without actually being a comic book story! Wow!