Not exactly the coupon/special offer kind of deal but given the popularity of the nForce 2 chipset I was surprised when I noticed Shuttle and Biostar have motherboards being sold below the ~$80 mark (from our pricewatch section):

Biostar M7NCD Pro nForce2 400 Ultra
http://techspot.pricegrabber.com/search_getprod.php/masterid=1074073

Shuttle AN35N nForce2 Ultra 400
http://techspot.pricegrabber.com/search_getprod.php/masterid=976446

You can grab an 8RDA3+ for $95 at mwave.com, you'd think if you bought a mobo for ~$80 you'd be able to afford +$15 for a top-of-the-line board.