Don't be afraid to wear your training wheels. Pre- and post-roll may be the targets of widespread industry scorn, but they're occasionally used effectively.
 
"The sexy, grand slam, home run stuff is great, but most people build brands and sell products in a far more 'one brick at a time' manner," says Randy Killgore," CRO at Tremor Media.

Examples
Hugo Boss' recent pre-roll campaign
"Luxury goods companies have been slow overall to embrace digital advertising," says Kilgore. "Hugo Boss ran a nice, aggressive pre-roll campaign for its non-clothing products that I believe probably surprised prospects by choosing online video and thus freshening opinions about HB."

"Saw III" post-roll campaign
My personal favorite was a post-roll campaign orchestrated by Palisades Media Group for Lionsgate's "Saw III" that ran on Break.com last fall. Jigsaw, the creepy "Saw" villain, addressed Break.com users specifically and told them he was watching them. The shock value was so great that I looked for more videos on the site that were hosting the post-roll -- a complete reversal of typical user aversion to in-video ads.