Fan Comics
Browse the pages and if you get inspired, go ahead and pick up that pencil, or open photoshop and make some art!
Day After Day of the Tentacle
Michael Nusair was one that saw humor with the way the characters of DOTT work off each other. So he proposed "What if those characters didn't go home after the experience.", "What if Horse came into the future [somehow]?" , "What if we could get the tentacles back [in what is even more inconceivable]?". Then he decided that a web comic would best suit their mis-adventures. And it was so.
There are 72 strips in all, plus 17 guest strips, over at his site. If the site goes down (hopefully not), I will house the strips here, along with the ones not in the DADott Viewer here on the site.
Howard & Nester

Not so much a "Fan Creation" but it is a fantastic comic from Nintendo Power, and not from LucasArts, so I figured it could go here and fill up some empty space.
If you would like to submit your own, send them to Maniac Zombies.
Sam & Max

From the desk of Steve Purcell comes a comic very loosely based on the Maniac Mansion world. Actually, I don't even see a connection, but hey, it works for me. If you would like to submit your own, send them to Maniac Zombies.
Send in your own!
If you would like to submit your own, send them to Maniac Zombies.