Red Side has produced a fascinating video comparison of the fastest man-made objects (so far). It's quite entertaining.
I was amused by its reference to an ultra-high-speed manhole cover, launched during Operation Plumbbob in 1957. It wasn't actually a manhole cover, but a 2,000 pound steel cover plate over a 500 foot borehole used for a nuclear test explosion. It's presumed to have been vaporized during its passage through the Earth's atmosphere after the big bang.