If you're a creative writer--a poet, say, or perhaps an essayist--you may find yourself struggling to find just the right word. Perhaps you need a good rhyme, or you're trying to write in a particular meter. Rhymesaurus might be able to help.
Rhymesaurus includes a standard dictionary, albeit an out-of-date one; a thesaurus; a rhyming dictionary; a "sounds like" tool that helps you find words that, well, sound like the one you've got in mind; a nifty WordSurf feature that lets you hop among terms related to your word; a pattern search that helps you find words of particular syllables, lexical stress patterns, and beginning and ending sounds; and even a basic text editor.
The interface is Spartan, but fairly self-explanatory. Tabs at the top of the main window give you access to the various features (like Dictionary and Rhyme). You enter your search term in the Word to Find field and click a tab to begin a search; sometimes you need to click the Search button. Arrow buttons near the top let you navigate through your search results. A File menu at the top is applicable only to the ScratchPad text editor.
The Dictionary feature is fairly limited, since it is based on the public domain portion of Project Gutenberg, which is itself based on a 1913 edition of Webster's Unabridged. In my tests it couldn't return results on many words that the merriam-webster.com site defines. Nonetheless, the rest of the Rhymesaurus features are robust and could be very useful to a writer.