I can't remember titles of these stories

I remember in school reading some stories, but I don't remember the name of them. The first story is like a goosebumps story. The setting is Highschool, and it took place in a modern setting (modern at the time the story was written). I remember that the characters felt one of the girls in Highschool was extremely superficial because she always had to apply her make-up on every so often. At some point in the story they end up in a black-and-white world made up of a handful of highschool students who in turn are black-and-white themselves (Imagine the world looking like a black-and-white photo and that's what it looked like). Anything exposed to the world would slowly turn gray. They used lipstick to get back to their world (because the cap on the lipstick prevented it from turning gray and it allowed them to return back to their own world). While in the world they learn that the girl they thought was superficial was in fact one of the highschool students who ended up in the black-and-white world and she continues to apply make-up to cover up her now gray skin. The characters make it in time to get their class photo taken, but the guy taken the photo is in fact the guy who used his magical camera before to send the characters to the black-and-white world, and they get sent back to that world. That's all I remember about the book, I remember being short and I think it was less than 200 pages long. The other story I can't remember is one that takes place in a modern setting and I think it takes place mostly in a suburb. The characters find pills that I believe accidentally ended up on earth by aliens. The pills would enabled whoever consumed them to think they were a famous person and perform a task that they were known to do with complete mastery. The downside to the pills was that you had no idea how long they would last for, and you didn't remember what you did while under the influence of it. Which means that you could be crossing a tight rope while hundreds of miles in the air, and the pill could stop working. I believe there were three main characters: two were boys and one was a girl. I don't remember what the conflict was in the story, but I remember liking it and I remember it was a pretty long book (I think 300+ pages). Thank you if you know these stories!