okay so i have a question.
Dobby warned Harry something bad was gonna happen at Hogwarts that year.
he obviously knew that from listening to the Malfoys.
but i thought when Lucius gave Ginny the diary, he didnt know what he was doing.
i thought he just gave it to her because he needed to get rid of things that could connect him to the dark lord in his house.
or he gave it to her because he hated the Weasleys and he thought something might happen to them with the diary?
i know he had no contact with voldemort and he didnt even kno he was alive.
did he think the diary might have brought him back to life or something??
your thoughts, please?

Lucius might have an idea about Horcruxes then, he despised the Weasley's yes and that might have been another reason why he had slipped the diary on ginny's things. Maybe it was all part of the plan.

or maybe you're quite right that he just wanted to get rid of the things that might connect him to the dark side.

I was the first one.Ü

Hm. I think that he want to get Mr. Weasley in trouble. Just think, Mr. Weasley have spent years protecting Muggles with the laws, and now his daughter is found to be attacking Muggleborn? Remember, Dumbledore told Harry that the Death Eater didn't know the meaning of Voldemort's statement about how he have gone "further than anybody" on the path of immortal life. (I'm not sure about what he said exactly, I don't have HBP or GoF with me now.) And by that statement, Voldemort meant his Horcruxes.

I'd have thought that he suspected something was up because of the Dark Mark. Wasn't that supposed to turn darker or move or something when Voldemort was getting more powerful? So, if the tattoo changed, he'd know something was up - just not necessarily what.

Dumbledore said that Voldemort didnt tell Lucius that the diary was a horcrux, but he might have said that it would cause the Chamber to open again:
“No doubt he thought that Lucius would not dare do anything with the Horcrux other than guard it carefully, but he was counting too much upon Lucius’s fear of a master who had been gone for years and whom Lucius believed dead. Of course, Lucius did not know what the diary really was. I understand that Voldemort had told him the diary would cause the Chamber of Secrets to reopen because it was cleverly enchanted.”
HBP, pg. 508

i think he just wnated to get rid of things that could connect him to the Dark Lord

here's my theory:
He was trying to get rid of things connecting him to voldemort, and he thought it had something to do with the chamber, so he thought by giving it to Ginny not only would it cause turmoil at hogwarts but it would also bring down the Weasleys.