The Time Hackers
by Gary Paulsen @
Good sci-fi read for fifth grade and up.
In the future, we can observe past happenings with our computers. You can visit them, but you can watch a hologram of what has happened. Of course, there are restrictions to what you can watch, kind of like how movies and TV are rated today. But someone has figured out how to bring the events to life. It is no longer a hologram; this someone is playing practical jokes on Dorso and his friend Frank.
As the pranks begin to escalate, Dorso and Frank have to figure out who is doing it, why, and how to stop it before someone gets seriously hurt or their timeline is changed.
Quick, short read.