To date myself, I took a "unit record" business course in High School, because I wanted to program an IBM 402 accounting machine before they disappeared from the planet.
I keep current by reading, talking with younger colleagues and investigating interesting things (like Arduino) on my own time. Sometimes, my ancient knowledge comes in handy (neither my boss nor my lead software co-worker had read Brooks' Mythical Man-Month). I offer soldering lessons and have been asked to repair older gear here at work.
My independent investigations of new tech have made me the go-to guy (well, I am the only hardware guy here, now) for quick mockups, because I can hack together stuff for demos. Years of valuable experience in making mistakes help me know what not to do, which I try to pass on to the younger people who work here.
Linux is new to many, and the command line is scary, but a former employer dropped Sun workstations on our desks and told us to set them up, so I learned "survival UNIX" the hard way. It still pays off today, the Linux system on my desk lets me do things that aren't as easy to do on a Win7 system.
If you stay curious, you won't be outdated. And some of that ancient knowledge can come in handy -- it's called "experience" and passing it on, in a low-key way, is a good thing to do.