Dice Drop Generators differ from All The Dice Tables/Generators in that instead of being a collection of tables to consult, the placement of the dice as they land on a blank or pre-printed sheet determine the results.
Random Dungeons from Buckets O’ Dice is a method of generating random dungeons. Dump all the dice you own on a sheet of graph paper, those that miss the paper take away. Those that roll their max, keep in place and remove the rest. The value on each of the remaining dice indicates room size. d4 = room size 4, d6 = room zize 6, etc. Read the rest at the link for details.
A variant on Dungeons from Buckets O’Dice is Five-Die Dungeon Generation. Similar to the above, but 5d6 are used, ignoring those that miss the paper.
I haven’t turned up other Dice Drop Generators with a Google Search.
[Update] Google+ has a community called Die-Drop Table Heaven.
If you know of a Dice Drop Generator, please share.