I found this tonight while doing a little writing research. (Okay, I was trying to come up with titles for the as yet unwritten - and unasked for - sequels to DLN. So sue me.)
You can type in the beginning of a word and find all the other words that begin the same. Or even take a chunk from the middle of a word and find all the words that have the same middle. Supposedly great for crossword puzzles, but it hit the mark for me tonight.
If nothing else, it's a fun and writerly way to waste time. Like we need any more of those. ;o)