Time Travel Warriors

Although things happen to the Worthington family, Luke and Scott never imagined in a million years that they'd ever create a time-travel machine. But they have, and now their adventure begins.
Hurled back and forth in time, they come face-to-face with ferocious dinosaurs, fight gladiators in ancient Rome, and fly spaceships in the distant future.
Helped in their struggle to return home by Percy and Troy, elite time-guardian warriors - all they have to do is find the mythical Crystal of Time, capture an evil time guardian, and defeat a skeleton army that cannot be killed.
No pressure then.