What do you call it when people mix truth and lies?

Though not specific to that technique, what's being done there is the use of half-truth, which comes pretty close. http://en.wikipedia.org/wiki/Half-truth

Disinformation - You are providing information while also knowingly spreading lies.

When I partake in a few adult beverages this is my favorite past time. Any time I can provide insight on something in a conversation, I like to follow it up with a small tidbit of bullshit. The more obscure the better. And if it is really good then they have no chance at googling an answer.

Example #1

Friends were discussing Buffalo burgers and I mentioned their low fat/calorie content, which was then verified. I then went on to talk about how the buffalo became endangered because they would not cross train tracks during their migratory process and soon just died by the tracks.

Example #2

A special was playing about Mark Twain and my kids were watching it. Soon a few guests started watching it, and his name came up and I told the meaning of marking a twain as a riverboat captain. Right after that I mentioned that Mark Twain used the name "Huckleberry" because he was allergic to Huckleberry jam.

Example #3

Friends were talking about the Dish Hopper and the use of kangaroos in their ads. I mentioned that it was interesting because a female kangaroo is a flyer. Then I went on about the name Joey for a baby kangaroo - telling a story of an Englishman convict that had escaped from penal camp and hid with a group kangaroos. And of course his name was Joey. Joey was also the first person to notice that kangaroos cannot walk backwards.

Now that my friends have caught on a bit they tend to not believe anything. But I see them checking their phones secretly a minute or two later and that makes the disinformation even more fun.

Also sharks cannot get cancer.