You can't chuck a box of Tentacle Chow anywhere in Germany without it hitting someone working on a Maniac Mansion fan game. But the one brought to my attention by Cyrus7 on our forums is a little bit different.
Crazy Mansion presents an original story that takes place in the universe of the Maniac Mansion while adroitly sidestepping copyrighted names in order to escape legal problems. The team is a group of longtime friends and Maniac Mansion fans who call themselves Desperate Studios and have apparently been tinkering with homemade game development since the Commodore 64 days.
They seem to have gotten far along enough in the conceptual phase of Crazy Mansion to show off a bunch of stuff and are trying their hand at crowdsourcing the game's development - check out their indiegogo campaign where you can read an overview of the project as well as see a bunch of concept art and the following trailer. I do like the art style they've landed on: