Sibelius user Kyle Gann is, in his own words, a “composer, musicologist, writer, educator”, which means that he must always be very busy! On his ArtsJournal blog, PostClassic, he writes engagingly about a variety of contemporary music topics — and, every once in a while, about Sibelius.
In his post The Things You Can Steal From Students he talks about a discovery made by one of his students:
For some reason I’ve generally shied away from tuplets-within-tuplets, but Ben had come up (accidentally, he admitted, by punching the tuplet button twice instead of once) with a scheme for a quasi-irrational but actually elegantly geometric acceleration and ritard.
You can see and hear some more examples of using nested tuplets to produce rit. and accel. effects on Kyle’s blog. Couple them with the new feathered beam feature in Sibelius 6 and you can even double your fun.
(Of course, whether you actually consider this fun at all is entirely down to you!)