Advertising is an art and if a marketing guru is also creative, they can reach beyond the boundaries of the mundane and boring and design an ad that will be remembered for a long time (or at least a few months). As a society, we associate commercials as a bad experience, only comparable to going to the dentist. For outdoor billboards, you have the added disadvantage that these are typically viewed in the seven seconds someone is driving buy. This means the advertisement has to be noticeable, creative, potentially funny and grab the attention, in 7 seconds.
Here are some very creative outdoor billboard ads that could be award winners: