Oblige is the ultimate random Doom map creator, and this new version takes the cake!
I have just released version 7.50. This is a major rework compared to 6.20, introducing a new system of generating levels based on the concept of Shape Grammars (a somewhat rudimentary application of that concept, anyway). The results are definitely better than previous versions, though it still does some stupid things sometimes.
You can download it at the OBLIGE homepage.