So, a fourth season of Slayers was announced years after the third season ended, and you didn't understand what all the fuss was about. It was just some old show, wasn't it? Not even close! Slayers is probably the best fantasy comedy anime ever made, and to no Japanese reader's surprise, since it's based on Hajime Kanzaka's uber-popular light novel series (over 30 volumes to date!).
But a lot of younger fans may never have gotten a good shot at watching Slayers. It is an older show, and less focused-on, so by the time the new seasons (Slayers Revolution and its followup, Slayers Evolution-R) started, it'd be too much trouble to catch up on the canon, so I think it got shrugged off.
However! I recently noticed that the first (and second) seasons of Slayers are currently up on Hulu. At the moment it's dub-only, as it looks like FUNimation doesn't have the digital-streaming rights to the sub version just yet, but Slayers has a pretty solid dub-- Lisa Ortiz does a good job of voicing Lina Inverse, even (in my opinion) mimicking Megumi Hayashibara's pitch and style. (Note: she did the TV series dubbing, but Cynthia Martinez did the OVAs and movies.)
So, the plot: Lina Inverse is a pint-sized and young sorceress of immense power. Sometimes she uses that power for good (she's always willing to save the world), and sometimes for...not so good (when she's pissed off, hungry, or greedy...which is most of the time). Throughout the first season she's joined by a rather dumb but skilled swordsman named Gourry , who assigns himself to be her bodyguard. Along the way they make any number of friends, including the emo chimera Zelgadis and the would-be-superhero, Princess Amelia . Each season features wacky adventures, growth to the impressive world-setting created by Kanzaki (think D&D-- black mages, white mages, dragons, etc), and eventually a world-saving quest of some kind.
I know it might be daunting to want to try since there are now five TV seasons and all those OVAs and movies-- I'd say to start, skip out on the OVAs/movies entirely, and just take the show one episode at a time. Starting with the first. And if you like it, you can move on to the second. And if the whole first season is enough for you-- and I'm betting it won't be --then you can stop there. (And if it's not, hey, the second season's available too!)
To get you started, here's that first episode, and here are all the rest in the first season . Enjoy!