Mark Bittman, in his NY Times - The Minimalist column explains transforming your own traditional/typical yogurt into a thick, cut with knife, greek style yogurt!
I have not tried this myself yet, but hope to the next time we make up the dip.
Crumbled Gorgonzola or Blue Cheese
Red Onion or Shallots
Mix it all together to taste and voila!
*Does get better if you give the dip time to set and the flavors to meld together.