Warning: If you tend towards the squeamish (or if you're male), proceed with caution.
After reading about using sea sponges instead of tampons on one of my favorite blogs, I decided it was worth a shot. I had my reservations, of course, but so far they have all turned out to be warrantless.
I purchased Sea Sponge Tampons from GladRags, where I had previously purchased reusable cotton pads that I would also highly recommend. They are extremely comfortable, and there's no annoying string to irritate me. They couldn't be simpler to use; you merely rinse it out and put it back in. No garbage and no concerns over Toxic Shock Syndrome. Plus, they don't dry out the girl parts like regular tampons do.
As of right now, I can see no downside to them at all. I suppose for women like one of my former co-workers who was horrified and disgusted with me when I offered her an OB (it boggles my mind that you could be an adult with two children and be afraid of touching your private parts but whatever), then this product is not for you. But if you are someone that is concerned with lessening your impact on the environment or if you are economically motivated, then I would suggest replacing the tampons you normally use with the uber-comfy sponges.
Thanks for the inspiration, Riana!