A rook lift, sometimes known as a "rover" or "rook up and over", involves first moving a Rook forwards on a file and then horizontally on a rank. For example, a simple rook lift is demonstrated in this Adler Variation line of the Budapest:
Rook lifts can be very effective at transferring an otherwise inactive rook into the heart of battle, and their potential should never be underestimated by either defender or attacker. Even the great Kasparov himself has used it effectively in top level games.
Kasparov's rook lift was much deeper and more complex than the first example, which just shows that a rook lift is a versatile strategy that one should be on the lookout for in one's own games.