Looks like there's quite a nifty little sale going on at Amazon for everyday Riedel glasses -- they're selling the 4-pack of the "Red Wine Glasses" for $23.99, but they're also throwing in for free a 4-pack of the "White Wine Glasses" as well. I don't have any personal experience with the Ouverture series, but it looks like a fine price to me.
The link below leads to another board that has listed all of the various discount coupons available for use at Amazon (all props to the dvdtalk peeps). Using one of the $5 coupons there will bring your total shipped price down to $18.99 for 8 glasses, or $2.37 per, just the right price point for those rowdy guests who like their wine a little too much.
To take advantage of the deal while helping out this site, find the Amazon link on the homepage and type in "Riedel Ouverture". Enjoy!