I retired last summer at the crusty old age of 38 and have been dicking around with my home lab ever since. I've decided that computers are much more fun as a hobby than as a job.
I retired from the US Air Force, where I served as a sysadmin for 20 years. With my pension and disability pay, I'm able to live comfortably without work now. I could go back into the field and easily double or triple my income... but then I won't have all the free time to enjoy my life like I'm doing now. So, retired life is good enough for me.