DanDanDan:

Elementary? Not too sure how old you mean exactly, but my own are between 12 and 15, and enjoy reading, including these:

Skeleton Hiccups by Margery Guyler

Beware by R.L.Stine ( a collection of stories plus a couple of his own)

Raising the Dead by David Cohen, (all you'd want to know about the undead)

The Berenstein Bears and the Spooky Old Tree by Stan Berenstein .