I'd say Strike Witches. It's still airing, but it's supposed to be... 12 episodes IIRC. Right now there are only 3 out, but it's a pretty fun show. I need more anime like this one. All girls. So cute. -__-

So, I herd u liek lolis.

Also how is the Toronto Metro Area (living there)?

Letsee, I end up watching a lot of anime with series only about 13 episodes long, so letsee if I can think of any that you'd probably like.

Aishteruze Baby is really cute if you're into that sort of stuff, from what I remember it's only 13 or so episodes long
Princess Princess never fails to deliver laughs, it's 12 episodes or so
High School Girls is pretty short, and it's silly, kind of reminded me of Azumanga Daioh in bits
If no one's reccomended Strawberry Panic yet, wacth it, that's an order.
I``S Pure is ok, haven't watched any but the first couple episodes, I didn't get much into it but you might
I was gonna say Kyou Kara Maoh for a second there, but then I remembered it's pretty long though. It's pretty interesting though, if you're in the mood for a long series that you can really get into, and has good character developement.
Can't think of any more off the top of my head. Mai HiME and Mai Otome are must watches though, they're 26 episodes each, but they're definitely worth the watch. I'll edit this post later if I can think of any others.

Edit: I My Me Strawberry Eggs is a very good anime too, I highly reccomend you watch it.

Serial Experiments Lain - 13 episodes of mindfuck

Dual! Parallel Trouble Adventure is one of my favorites...it's only 14 episodes long. It's a more comedic anime and includes giant robots. I usually don't watch anime with giant robots, but I really enjoyed this one.

You could check out Dragon Half or Yokohama Kaidashi Kikou. Both are very short series... The former is only one episode, and the latter is two.

The Read or Die OVA is also good, as is the TV show (3 episodes and 26, respectively) as well as Paranoia Agent (13), FLCL (6), and The Melancholy of Haruhi Suzumiya (14).

Hey thanks guys, I have a bunch of stuff to find now!

Baccano! is another cool short series. Has a Quentin Tarantino/Guy Ritchie vibe to it.

DearS

11 episodes long if i remember correctly. All of them on youtube...

Is about aliens that are actually kinda like robots but arne't their living but their sole purpose in life is to be a slave to their human masters.

Kinda okay.

Murder Princess - 6 episodes long

Mnemosyne - 6 episodes.
http://en.wikipedia.org/wiki/Mnemosyne_%28anime%29

IIRC Crest and Banner of the Stars are both 13 eps long.