I'm a computer scientist and I love my job nowadays. I hated being a consultant, too much waste and excess for my tastes. But now, I'm doing programming/database support/new technology stuff for one of 14 Comprehensive Cancer Centers in the US. Technically I am on the University's School of Medicine payroll, but I do far more work with hospital and Cleveland Clinic personnel than University folks. I'm currently doing support for a project that is trying to prove that something called Barrett's Esophagus is an inherited defect. Barrett's is a very good "early warning sign" for throat cancer (Esophageal Adenocarcinoma in fancy doctor-speak), and of course the earlier cancer is detected the easier it is to treat.
I usually just tell people that I work in cancer research.