Here's a couple from one of my regular marshalling locations - but I'm not directly involved in either of them.
Oulton Park GT race from 2006
(no-one injured - not even that marshal, although you'll see some orange through his black waterproof jacket after he stands up, this is where the rear bumper caught him)
[youtube]OAvc0Cij7zA[/youtube]
Oulton Park GT race from 2008
(minor burns to the driver)
[youtube]o5t_477Ak98[/youtube]
[youtube]eV99_BIqY4g[/youtube]