Doujutsu literally means eye jutsu. these jutsu need special kind of eyes like sharingan of the Uchiha clan.
Itachi no Mangekyou Sharingan
Itachi could create many genjutsu with his sharinagn but the most infamous genjutsu is Tsukuyomi, by looking at his opponents in the eyes he could create the worst nightmare which also effects the psychological and physical state of the victims. amazingly, it could happen in split seconds in the real world, whereas the illusion could last for days. another doujutsu called Amaterasu could burn anything in sight with black flames. also his final jutsu called Susanoo.
Sasuke no Mangekyou Sharingan
finally Sasuke awaken his own mangekyou sharingan and it seems to have a special power which he never discovered before. during his battle with Hachibi, he accidentally put out Amaterasu's black flames which burn Karin with his mangekyou sharingan. before Itachi met his death, he transferred all of his doujutsu to Sasuke thus now Sasuke has more power than before. there will be more suprises of his sharingan coming up i guess.
Kakashi no Mangekyou Sharingan
in the Part 2, Kakashi invented his new sharingan skill. eventhough it's called as Mangekyou sharingan but it's quite different with Itachi's mangekyou we've known so far. Kakashi's mangekyou works by concentrating the vision to a certain part of the target then suck it off to another dimension or in other word, disappear. he used it in his battle with Deidara when he took off Deidara's right arm. however he cannot use it too much cuz it needs a lot of chakra.
Madara no Mangekyou Sharingan
amongst all sharingan users, only Madara who made to awaken the final stage of mangekyou sharingan. he got the final stage by taking his lil bro's sharingan to replace his sharingan which already turned blind. nothing much known bout the real power of these sharingan yet.