Well, in one episode of the original "STAR TREK", Aptly named: "ALL OF OUR YESTERDAYS", the Enterprise is accidentally thrown back in time when the ship flew a little to close to a black hole...
To get back to their own time they flew around the sun at warp 8, and were sling-shotted faster than possible through drive...
For a very short time they were traveling at HYPER-WARP velocities...
cool huh...