Mitsudomoe is one of the most entertaining manga I had the pleasure of reading, every single short chapter has gotten laughs out of me. Every character is memorable, distinct, and loveable, including the background characters who don't even have any actual lines. Reading the manga you can appreciate the wonderful artwork of Sakurai Norio, as well as her skill growth as she continued to work on the series. There is an anime adaptation which does a really good job of capturing the humor and style of the manga, but you will be missing out on a lot of great content if you don't read the manga, as the anime is unfortunately a little too short, adapting only up to the starting couple of volumes.
I bought a used complete set of the manga from Manga Republic, and they all arrived in pristine condition, and now adorns my shelf as one of my favorite manga series.