Masuda Kousuke Gekijou Gag Manga Biyori

Both anime feature very short episodes and a very odd sense of humor. 

Short sketches of mostly completely obscene material. Both hilarious gag shows. 

Gag Manga Biyori doesn't make much sense and neither does Cromartie High School. Both shows seems similiar in the way they are animated. Gag Manga is still a bit more random since there is no exact storyline unlike Cromartie High School. Cromartie High School still has main characters. Gag Manga has a couple of returning characters but mostly is new poeple in every episodes. Both are weird, strange and leaves your mind broken... 

Both have similar fast-paced styles of crrude humor. However, the episoides in DMC follow an actual plot, whereas Gyagu Manga Biyori tends to resort more to randomness. 

If you're into comedic series that are nothing but a couple of separate short stories per episode, both series are a must. A fair word of warning though, as they also both contain some pretty suggestive humor, Mankatsu more so than Gag Manga Biyori. However, if you liked the one, you're surely gonna enjoy the other.  

Gyagu Manga Biyori is more for short unconnected stories, Ping Pong Club has some storyline and a bit more sense, but humor is similar in both of them: wacky, vulgar and sometimes very topical. 

Both are really weird, and they are hilarious when you're in the right mood.  

Gags and jokes that may go over your head from the absurdity + odd animation=comedy goldmine. 

Both of these anime are gag anime that make you laugh out loud real hard. Saiki Kusuo is more straightforward in its comedy while Gag Manga Biyori is filled with more random and bizarre moments.  

Similar shitpost vibe of the commedy with weird/absurd punchlines. 

Weirdness combines with sick humor 

Neko Rahmen is a extremely random anime, Gyagu Manga Biyori is even more random! 0_o  

Both give random fun. It may not be as funny as Keroro but just as random. 

Short episodes of fast-paced joke. Gag Manga Biyori is random arrangement while Kuruneko is character centric. There are two ways to say jokes in anime. First is to use poker face and normal voice, usually derived from manga that has shorter dialog. Another is to use extreme facial expression together with loud voice, this usually an adaptation from comedy manga with lengthy dialog. However Gag manga and Kuruneko deliver jokes using both. To be precise, voice acting is the first reason that come to your mind when relating these two shows together. I'm no professional myself but I believed anyone can find similarity in the voice acting of both shows. read more 

Short episode filled with only jokes Gag Manga used original jokes from manga writer, can be easy to interpret for those who familiar to japanese manga, or impossible to understand for some net-surfer that happen to pass by Charady used known jokes from all over the world. This can be a drawbacks If you are familiar with some jokes or it is local to you, you may guess the joke beforehand and ruin your fun of the whole episode. Without any of these accidents it is ensured to be entertaining, it's a joke after all. 

Both are short animation (5 min) Gag manga Biyori is hard to understand and the joke is very japanese oriented. But if you familiar with comedy anime you should have no problem watching it. Hetalia is a historical anime, knowledge about world history required to understand most of it jokes. But if you never read the original four panels manga, you may still have some trouble understanding it. Gag manga is more audience-friendly. SUM : Gag Manga require some knowledge about japanese language and culture to fully appreciate the jokes. While Hetalia require an A++ in your high school world history class, and strong sense of anime interpreting. 

Super fast-paced Japanese gag manga, complete with Boke-Tsukkomi element. Each gag is short and played fast so even with japanese knowledge that understand school life comedy, you may still need to resort to fansubs. Tono to Issho resort entirely to parodying historical material, particularly the sengoku era. Gag Manga Biyori parody pretty much everything with plenty of original fun, and also feature a lot of historical parody. 

Fast- paced speech comedy, rely a lot on conversation to be funny. (Like Gintama, both shows speak a lot and are not very funny muted.) The voice actors are skilled and contributed much to the funniness of the shows. Jokes are original and have something beyond the same old Japanese Manzai boke-tsukkomi style. Pacing is also done great, move on from joke to joke before you can stop the first laughing, a trait of good comedy. 

A small package of senseless but fun animation, made of original joke with some historical references 

Fast-paced nonsensical five-minutes long high-tension comedy. Complete with easy-going student artwork style and quick-speak voicing, everything in both shows fits the description of high-tension comedy you often found in Japanese comedic content. Double J story is written by comedic genius Nonaka Eiji of Cromartie high school, he is great with historical and cultural reference. While GMB is written by Masuda Kousuke, who write faster-paced script, but with no less historical reference, pop-culture parodies and boke-tsukkomi jokes. 

If you like crazy, random humor, with some weird loose reference to history, you will like this series. I saw on japanese blogs that peple who like Gintama often like GMB.