Techcrunch and WebmasterWorld have recently reported that Google are trying out custom meta descriptions in Google result pages

Google Bucket Tests User-Defined Blurb Length In Search Results

Via a "Bucket Test" (where random members of the public see the new beta feature, similar to the Digg style voting on results previewed a few months ago), users can select between no meta description (small), the standard description (Medium) or extended description (Large) It is unclear at this time whether this will mean Meta Descriptions should be extended or whether the extended descriptions will be scraped from the page content. I can see a good use for the extended descriptions to get a better idea of the page before clicking through, so spammier sites will be more easily identified.