DISCLAIMER:
Okay, so before I get angry comments below, let me clear something up. YES this post will be slightly sexist. YES this post will assume that some people did not spend their childhood in 'geekdom' but are enthusiastic about joining the fun later in life (no, that is not being a poseur). And YES I know there are girls who like geeky things, and may not particularly like what I mention here. So if you still insist on being nitpicky, fuck you.
---------------------------------------------------------------------------------------------
Without further ado, here are a few things you (as a girl, or a guy if you so wish) can get into if you wish to broaden your spectrum into the bright and nerdy, but don't feel like jumping right into 'all that stuff everyone keeps on talking about'.
Sailor Moon: You've probably heard of or watched Sailor Moon before. In a nutshell, it's an anime about a clumsy, obnoxious young girl who turns out to be a sort of superhero from the Moon Kingdom. Even though some parts are painfully obvious, it's actually a very entertaining show, plus it has pretty outfits, fun hair styles, and love dilemmas (even a talking cat!). Even better is that each episode is about 20 minutes long, so it's pretty fast paced. I really recommend Sailor Moon if you want to get into anime. It's a gateway anime.(Yes, I am hilarious). Direction: anime, cosplay (easy, and pretty cosplay)
Pokemon: Pokemon can be a bit hard to get into for girls, and I think the main reason for this is that so many of the main characters are boys (until Misty comes along). As a child I loved watching Pokemon, but now when I watch the episodes again, although entertaining, they can get a bit repetitive. I do recommend it, at least the movies (especially the first 3). But Pokemon, luckily, is not just a show and movies. The best part of it are the games. So get yourself a GameBoy or Nintendo DS and buy a Pokemon game. They're easy to get a hang of and extremely entertaining, you find yourself playing for hours at a time. If you want to hit 2 birds with one stone, you can play the Pokemon game on Nintendo 64, though you run through it much faster. Direction: anime, gaming
Superhero movies: By this, of course, I mean all the Marvel and DC superheroes (for those who don't know: Iron Man, Hulk, Thor, Batman, etc.). The movies are actually all quite entertaining, and at least for me, got me interested in checking out the comic books (I didn't finish more than 3, but they got me interested!). If you want, you can also check out their older versions and compare the actors (personally, I found the older ones quite tedious). However, this is personal. The new movies though are action packed with a lot of attractive people, so you won't get bored... unless you don't like superheroes. HA, preposterous. Direction: superheroes, possibly comics
Harry Potter: Let's be honest, if you haven't seen or read Harry Potter by now, you most likely won't be into it. In this case I recommend you take another direction with your geekdom. But there is a possibility you never got the chance, or you remember seeing it sometime when you were young. You should revisit it, and if you like it, take a gander at the books. They're vastly entertaining, not to mention well written. Unfortunately you've missed the golden period of speculation between the book releases (who will love who? Who is evil?), but it's still worth a try. Like Sailor Moon, Harry Potter is a gateway to other magical worlds like Game of Thrones, and anything by Tolkien. Direction: magic, fantasy
Ragnarok Online 2: If you're into magical kingdoms and gaming by now, it's time to introduce RO2. A lot of people I've spoken to say that RO2 reminds them of World of Warcraft. Now I, personally, have never played WoW, nor do I intend to. But if you're looking to go into that direction, RO2 can be good for you. It's actually a simple role playing game, where you can if you want, play alongside other people, or by yourself. I, for example, am a magician and a blacksmith. You get to find pretty outfits and weapons, and fight against some (actually pretty cute) little creatures to gain combat and job points. The graphics and colours are wonderful, and there are no ugly monsters or gross scenes (at least so far for me). Plus, it's free! Direction: gaming
Okay, that's all from me for now. Once again, if you're feeling peevish, read my disclaimer please, because if your complaint falls under those categories, I will delete it. Fuck freedom of speech, ha.
If you have any questions or want more recommendations, I can help you to a certain extent. I'm no connoisseur, I am just dipping my foot in a very large pool.