Over the summer I looked into the possibility of meditation without religious trappings. One thing that came up was autogenic training, which is not meditation per se but frequently comes up in discussions on the subject. Autogenic training mostly involves visualizations and affirmations about relaxing various parts of the body. One thing it shares with meditation is that people are encouraged to practice it daily at regular times. I didn't really care for it myself, but others have had good experiences. If you're interested in trying it for yourself, click here.
Something that seems to be a little more my speed is passage meditation. It can be tied to a religion, but it doesn't have to be. Some freethinkers will probably be put off by Easwaran's use of religious language, and there's no doubt he was a religious man (he was Hindu and published his own translations of some Hindu and Buddhist scriptures). But in his book, Passage Meditation, he deals with that issue:
I hope you will understand that the word “Lord” here does not refer to a white-bearded gentleman ruling from a throne somewhere between Neptune and Pluto. When I use words like “Lord” or “God,” I mean the very ground of existence, the most profound thing we can conceive of. This supreme reality is not something outside us, something separate from us [emphasis mine].
For those familiar with Hindu doctrine, this could be interpreted as aligning with the idea that we are all one with Brahman. But it can also be interpreted as simply appealing to your own best instincts. And I think most people would agree that some of our instincts are better than others. That explanation may not be good enough for some freethinkers, but it's good enough for me. If you're interested, you can click here.
So those are my thoughts on meditation in a nutshell. Feel free to provide your own in the comments.