The vast majority of card makers and paper artists have dry embossed before, or at least know the process and are able to name a couple of different machines that get the job done. For those new to card making, dry embossing is simply the technique whereby a pattern is pressed into a piece of paper or cardstock to give a textured impression.
Embossing folders are the most common way to dry emboss paper and cardstock. There are numerous companies that produce these folders and between them just about every major holiday and theme is covered.
You can also add texture to your cardstock by embossing with score lines. I like to emboss on the diagonal, then flip the cardstock over and emboss the other way. It gives an interesting diamond shaped pattern with embossed and debossed lines.