I asked my direct boss's permission to be officially moved to the sales team, and spent most of that summer developing a custom CRM that facilitated the flow the sales staff used. When it was finished, the average number of leads contacted per associate increased 40% basically overnight, dramatically affecting the growth rate of the company (and the sales staff absolutely loved me).
Any software developer could have built what I did, and had the company realized what they were missing I'm sure they would have got one of their "real" developers to spend a couple of weeks and probably put something together better than what my intern-self was capable of. The value I added in that situation wasn't my engineering prowess, but rather my ability to see exactly what was needed and build the right tool for the job.