A tiny, vibrating motor, easily attachable to paper or fabric! Just connect 3-5V across it, polarity doesn't matter, and it'll BUUUUZZZZZZ!!!
The voltage (and hence current) supplied from LIR2032 rechargeable coin cell batteries may damage the Teknikio LED boards, so please ONLY USE CR2032 3V COIN CELL BATTERIES with the Teknikio range!
Teknikio make a range of fun and beautiful sewables (or stickables - you can use them in origami/papercraft projects too), that are designed with children and education in mind, but they suit explorers, inventors, and curious minds of all ages: 8 to 108!
They've also put together a couple of fab guides on sewables and origami to teach you the basics and give you some project ideas.