If you can crochet, and you have a bit of free time and scrap wool, then why not make some pieces for the Hyperbolic Crochet Coral Reef.
Here is their blurb, "This is a large-scale, handmade replica of the real thing. A woolly celebration of the intersection of higher geometry and feminine handicraft, and a testimony to the disappearing wonders of the marine world. Unfortunately, plagued by pollution, the real coral reef may not be with us for much longer. This project highlights the plight of the world’s waterways, especially on the Southbank, our own river Thames. Charity Thames21 took the exhibition organisers to see the problem for themselves, where they collected some of the plastic that causes part of the problem, to use in their crochet."
It sounds harder than it is. In fact the crochet is very simple, and you can have great fun experimenting with shapes and textures. There are patterns online for free but, if you're not sure were to start, have a look at www.theiff.org, for some great examples. For patterns try www.crochetpatterncentral.com, or to buy patterns try www.etsy.com
I'm going to try get some basic patterns up before the end of the week.
The exhibition opens on the 10th June through to 18th August, The Hayward Gallery, and Festival Hall, Southbank, London.