Do you have any budding poets in your family? They might really enjoy this unique online rhyming dictionary called Write Rhymes.
It's not your normal dictionary where you look up words out of context. Instead, you type your poem right into the text box—or paste it in from your word processor)—and when you want to find a rhyme, just option+click the word want to rhyme and Write Rhymes presents a list of one- to four-syllable rhyming words. Then just click on the word you want to use, and it's inserted automatically into your poem. Could it get any easier?
By the way, if you are looking for a poetry curriculum, my 9-year-old daughter has been using Building Poems by Michael Clay Thompson and has really enjoyed it.
This makes looking up rhymes rather convenient but the rhyming options are rather limited. If the author can make it as powerful as Rhyme Genie (http://www.rhymegenie.com/) it would certainly be a great app for poets.