This still somehow trumps the original for me.
People NEED to watch this show.
If you're not sure if you should try it, check these out:
Battle of the Humongonauts - War of the Gargantuas homage episode, complete with words getting stuck in somebody's throat.
The Shrieking Madness - H.P. Lovecraft Homage episode.
Mystery Solvers Club State Finals - Scooby Doo and other classic Hanna Barbera mascots have to save their teenagers
Escape From Mystery Manor - Classic Gang explores a spooky old house, only this one is underground.
Nightfright - Vincent Van Ghoul (Vincent Price homage from 13 Ghosts) invites Scooby and Shaggy to his mansion for dinner.
From Season 2: Beware of major spoilers in these episodes.
Night Terrors - Scooby Doo meets the Shining (more or less)
Heart of Evil - The gang encounter a Dark Knight Returns esque Blue Falcon + Benton Quest is tied into the origin of Blue Falcon.
There is a major story arc, but these are really cool episodes to check out and see if the show is for you.
Here's an image and is an example of the sort of humor: