There are plenty of activities to do during summer holidays, but if you haven't found any that suit you yet, I suggest you try poetry. Rhymesaurus will make it really easy for you!
This original application will find rhyming words for anything you write on its search field – well, for almost anything. Rhymesaurus contains about 35,000 words so there are obviously a few missing, but it worked fine for me for each one I tried (even swearwords, which we all know it's one of the first things you look up in a dictionary).
Search results include rhyming words classified according to their number of syllables, as well as idioms and proverbs that can also be used in your rhyme. You can set the program to highlight the most common words.
There's not much left apart from that: no configuration options or no extra tools, apart from the possibility to save your searches.
Rhymesaurus is a quite simple yet very original application that will find rhyming words for anything you type in.