I heard about this game called Lexicon from Jenileigh's forum. I decided to try it out for myself... this is the closest game to Blocktionary that I have found anywhere.
I downloaded the shareware version just to check it out,the graphics are just amazing. There is a version you can purchase to play with others.
For all of us Block addicts, I thought that maybe this would be an option IF Block doesn't resurface (bite your tongue DEM).
Here is the link if you would like to give it a try.