Pretty much every day throughout 4th grade I'd be reading a Goosebumps book (or an Animorphs book, if you remember those!). The ones I remember the most are Say Cheese and Die, the one with the Creeps trying to take over, and the one where they go to a black and white world in their school where there's no more color.
There also were some Goosebumps choose your own adventure books, and the one at the wax museum really scared me, especially the skin scraper device where they scrape the skin off of you to turn you into a wax figure.