UPDATE: Straight from Wikipedia: On June 26, 2013, Lucas Cruikshank confirmed on twitter that Nickelodeon has canceled Marvin Marvin. (FIREWORKS AND CELEBRATION IN TIMES SQUARE ENSUES)
Nick you have hit a new low. 10 years ago you were just as high as Cartoon Network and Disney Channel, but now as those channels seem to be recovering a bit, Cartoon Network especially, you're still going south. CN is starting to recover from their low, CN Real, and Disney the same, recovering with Gravity Falls and Phineas and Ferb, but Nick has gone down further. I would say the start of their problems was after the Spongebob movie in 2004, because that is when Spongebob started going down and eventually everything else. Nick has failed to produce a good show since Drake and Josh ended in 2007, and this show, Marvin Marvin, changes nothing.
I'm judging this show from one episode I watched, "The Toothache". The show is terrible. You obviously have Marvin, the weirdest person I've ever seen on any show on Nick, played by Lucas Cruikshank, making him free to make up weird words that might pass as funny. You have the brother, who is also supposed to be the coolest and "funniest" kid on the block. The sister, who is a stereotypical teenage girl and pretty similar to people I've seen on, lets say, 5 other shows. The grandfather, who is supposed to bring humor by his insults to other characters. The fathers never there, so I can't comment on him. And finally, the mom, who thinks she is the "Good job! Fist pump. BOOM" type of mom.
The humor is also terrible. All of the humor is based off either the crazy antics of Marvin or bathroom jokes. For example, when the teenage girl is talking to her friend after explaining why she can't see Marvin after he gets "The Toothache"
Friend: What's your family doing? What's Marvin doing?
Girl: Their probably having a farting contest.
Exactly. I don't know why Nick is investing millions of dollars in an 19-year old kid who made a couple videos on YouTube. They've given him 3 movies and 2 TV shows over the course of two years, none of which have been successful. I can handle the Fred videos online, since they are a length of 2-5 minutes long. However, 21-22 minutes of Fred or Lucas is unbearable. Nick's influence in its current years have ruined Spongebob, the Fairly Oddparents, and Dan Schneider. Pretty soon, the whole network is going to be ruined.