Shade sail - great way to give shade. Can be taken down when it's not needed. Loads of colour choices.
Waterproof Patio Sails | Outdoor Shade Sails to Protect Courtyard from UV Ray and Rain | House ...
Waterproof Shade sail 4 x 4m Square
DIY Pergola Retractable roof shade http://www.uk-rattanfurniture.com/product/beyondfashion-smlxl-waterproof-outdoor-wicker-rattan-garden-bench-furniture-protective-cover-patio-tables-chairs-cover-wicker-rattan-xl/
Structureflex offers the Waterproof shade sails which are the outstanding option for schools, playgrounds, swimming pools, backyard patios. It provides full protection from harmful UV rays, rains etc. http://structureflex.com.au/ShadeSails.php
shade sails carport - Google Search
Alion Home© Waterproof Sun Shade Sail...
Canvas providing shade instead of a more expensive umbrella - This would be easy to do - AL MARE
Retractable Patio Covers and Other DIY Ideas for Beautifying Your Decking | Louisville Deck Staining
Sliding Patio Cover for instant sun OR shade (This couple built a monstrous steel structure but these can be adapted to a small deck).