A slab serif font by Jos Buivenga (exljbris.com). Museo Slab 500 has an x-height similar to Georgia. It also has heavier, more uniform strokes which makes letters like a and e a bit harder to read. Thus, Museo Slab works best with a generous font-size.
The Museo Slab family has 12 fonts (various styles, weights). All are available for web licensing at fontspring.com. In the font specimen sheet, I show only Museo Slab 500 and Museo Slab 500 italic, which are free fonts. I combine them with Museo 700, a bold font from a different family, but a family with a similar structure. The full family is also available via typekit.