1.Gin's hair color has changed multiple times throughout the series, from light brown to blonde to silver.
2.Shinichi's favorite food is lemon pie
3.Out of all 390+ cases where Kogoro has been, he has actually solved less than 10 without being knocked out by Conan, and even during the less than ten cases he wasn't knocked out, he had assistance from Conan during most of them.
4.Gin is left handed, and his favorite weapon is the Beretta M1934.
5.Shuichi Ikeda, the man who plays Shuichi Akai(and Toichi Kuroba) (hehe) is married to Sakiko Tamagawa, the voice actress who plays Akemi Miyano (So it's almost like Akai (or Toichi) got married to Akemi!)
6. Eisuke Hondou once had leukemia!
7. Hakuba Saguru once stated to Aoko (and I quote) : "A man who is 180 cm tall, 65 kg weight, and was born on August 29th, under the virgo zodiac, who has group 'A' blood type...like me...is willing to go out with you." (I think he was attempting to flirt there by impressing her with his biological information)
8.Shinichi's address, Block 21, District 2, Beika City, Tokyo, was based off of the famous Sherlock Holmes address 221B Baker Street, London!
9. Although Gin is very intelligent, he always forgets the faces and names of those he killed (He must have killed a few too many to remember!)
10. Jodie is a bad driver, whereas her new FBI friend Andre is an excellent one.
11. Speaking of Jodie, her name is based off of Clarice Starling, an FBI officer and the main character in Silence of the Lambs, who was played by famous actress Jodie Foster
12.Gosho has hinted many times before that FBI officers may be BO members... he earlier implied that Jodie was actually Vermouth (before it was revealed she was an FBI agent) and that Andre was a BO spy.
13.Akai's favorite drink is Bourbon... that's pretty ironic... or maybe it isn't
14.The reason why in movie 13 Takagi finds Sango and Jugo's names so funny is because their names form a calculus equation! San=3, go=5, and jugo=15, and of course 3(san) X 5(go) =15 (jugo). Pretty funny, huh?
15.Speaking of the Yokomizo brothers, Sango's hair looks like coral, and sango also means coral in Japanese!
16. Kansuke once was pursuing a criminal he believed to be the killer of an officer from his childhood in the Nagano village, Kuroto Kai, in which an avalanche formed and caused him to lose his left eye (the scar) and movement in his leg, where he was believed dead until high school classmate and fellow officer Koumei found him while pursuing the criminal
17.Heizo and Okiya are the only two frequently appearing characters that never (or rarely ever) open their eyes
18. Korn and Vodka are the only two characters that are always seen wearing sunglasses (even while they're wearing a halloween mask!)
19. Officer Toyama and Heizo Hattori had once discussed Heiji and Kazuha and marriage... which must have been pretty awkward for Kazuha, who was pretending to be asleep in the backseat.
20. Officer Tomedoes appear in both the manga and anime, but his name was never referred to or mentioned in the manga, though it was claimed to be Officer Tome in the anime.
21. Kaito has a fear of fish, or ichthyophobia
22. The anime has messed up the story a couple of times; in episode 7, Gin and Vodka were supposed to be on a train Conan was on, which is where Conan discovers their codenames, but in the anime, they are look alikes, not the real Gin and Vodka, and they are arrested, so their names come up later. Also, Akemi Miyano was originally supposed to die in episode 13 where she pretended to be a little girl looking for her father, but instead she was killed one episode before Haibara's appearance while pretending to work at a bank she had robbed.
23. The English version of the manga and anime have also made some changes. At first, the English version named Gin and Vodka Melkior and Kaspar in the manga, but later on, they subtly changed it to Gin and Vodka. Also, there are name changes to everyone in the anime besides for Conan (they give characters American names), and there are name changes mainly to Shinichi (Jimmy), Ran(Rachel), Kogoro (Richard), Heiji (Harley), Megure (Meguire), Yukiko (Vivian) Yusaku (Booker) and Sonoko (Serena) in the manga. Also, in episode 50, Heiji (called Harley in English) subtly mentioned Gin and Vodka, because of the difference in the anime.
24. Azusa has gone through multiple makeovers throughout the series, as well as the Poirot coffee shop
25. Kazuha's name has also gone through a lot of differences in the English version. In the manga, her name is still Kazuha, but in the anime, her name is Kirsten Thomas, in the video games, she is known as Katrina Tolliver, and in the card games, she is known as Katie Thompson (this is one of the many reasons as to why the English version bothers me)
26. Out of all the characters in the series, Sonoko is the one character who has the most family members to appear in the series. Her sister Ayako Suzuki, her parents Tomoko and Shiro Suzuki, and her uncle Jirokichi Suzuki (and some even consider Lupin family) all have appeared in the anime and manga.
27.A lot of Detective Conan voice actors have also appeared in Ranma 1/2, such as Kappei Yamaguchi (Shinichi/Kaito) being Ranma, Kenichi Ogata (Agasa) being Genma Saotome, and so on.
28. Eri and Yukiko had both participated in the "Miss Teitan High School" pagaent but had tied due to Kogoro showing up.. although according to Kogoro, his vote would have lead to Eri winning.