RDFa is the W3C’s proposal for the lowercase semantic Web. As such, it is similar in spirit to the microformats initiative, but strives to leverage existing W3 work such as RDF. Manu Sporny produced an educational video on RDFa that you can watch below.
As Manu reminded me on the uf-discuss list, this video is more for education than for evangelization. Also, some aspects that I am personally interested in are missing, such as: drawbacks/features comparison and cohabitation with microformats, or explanation of choices made, but it is nonetheless very clear and quite entertaining for a topic that many would probably find very boring.