Whether you have a garden or backyard, dens are a winner with most children. Make from cheap tarpaulin, blankets or old duvets drape over patio table, chairs washing line whatever is available. If you add in things to dress up in even better. Doesn't have to anything fancy, scarf tied round waist or head make props out of cardboard, broomhandles, tea towels. Large cardboard boxes can be made into boats (add a long stick and a tea towel) or castles. A cheap underbed storage box with lid and a bag of playsand or fill with water. If you google Nature Detectives there are lots of ideas for activities, spotter sheets, colouring sheets, puzzles all free and for different age groups. I won't be looking after my grandchildren as I am working most of holidays but will no doubt see them at weekends. I love it when they ask if they can stay(6 of them aged 5-13) and sometimes all together. Hope you have a fab time... enjoy...... remember they don't have be on the go all the time, sitting looking at or reading books together, watching a dvd even singing can be fun too. If you are able to take photos and print off (even if only on normal paper) you could help them to make a little scrapbook of 'What I did at grandma and grandads. ' If printing off isn't an option perhaps they could draw a picture or two each day of what they have done.