I've never tried it, but a friend of my boss' did it with his company.
Their main business is in the money sector, so banking and investment kind of stuff. They bought a ton of links and effectively spammed their links on thousands of irrelevant sites. It was very successful for them at the time and they got a ton of leads through, even on irrelevant searches like "cheap nokia phones". Effectively, they pushed links on link farms and high PR sites and started building their own farms for their micro-sites. This was all done by one man, who didn't stick around long after this work was done.
All was well, until the Panda update hit them, hard. Over the next financial year they're set to lose out on around £1M in deals as the drop in traffic and rankings has forced a number of firms to pull out and go elsewhere. The harsh part of this is that people will now be losing their jobs, primarily in the IT and Marketing departments.