If you're tired of the ubiquitous foam alphabet tiles, these Korean play mats offer something at least a little different. We've tried them out and they're pretty thick and comfortable. If you get tired of the colorful side, the other side has a wood floor pattern.
They're not cheap, but they'll probably hold up a lot better than the alphabet tiles as well. Plus, we just think they're cute. If you live near a large Korean grocery store like H-mart, you'll probably be able to find them there. If not, we found a great selection at Little Seouls. They also have those alphabet foam tiles with the Korean alphabet if you want to encourage another language!

Nomade Express Slee...
My brother just came back from a visit to the Philippines and brought back a banig which is foldable mat made of palm leaves. http://www.tribo.org/textiles/banig.html
It's very comfortable and my daughter loves doing tummy time on it.