In general, I'm thinking about hacking biological systems (or, hacking DNA). This is still a pretty niche area, but is becoming more popular...
Rather than trying to explain it myself, there is a pretty good video at http://diybio.org/about/
(4 min) which discusses some areas of research/experiments/etc. Make magazine volume 7 (http://makezine.com/07/
) contained some good articles, and the current h+ magazine has some related info on "DIY Transhumanism" (http://hplusmagazine.com/magazine
An overlapping topic is "synthetic biology" which aims at developing a method of engineering biological systems. An annual competition called the iGem competition (International Genetically-Engineered Machines) started at MIT, in which teams build cells containing some useful custom-built biological system. They build these systems by using (or building their own) reusable biological components called "BioBricks" (think capacitor/transistor/attenuator, but biological). The competition was originally only open to institutions, but recently opened to amateur teams (I hear).
I'm a software engineer, and am used to hacking source code. Hacking DNA, though, interests me and is becoming a real option quickly. The learning curve and costs are pretty steep though, and I'm interested in finding other interested parties...