Check your local library for summer reading activites
Does your local library have a summer reading program? Ours does, and my son (a new reader just out of kindergarten) can't get enough of it. For every 30 minutes he reads, he gets to color in a spot on a game card. Depending on how many spots he colors in, he wins prizes. Brilliant!
This summer, we're having daily reading time -- perfect mid-day sun break or post-lunch mellow activity. My son reads his books (silently or aloud), I read mine (Me! Read! My books!), and my almost 3yo daughter listens to her brother or flips through her own books. She's part of the program, too; being read to counts, so even though she doesn't read she can still participate.
I can't tell you how good this feels. My kids see me reading (and enjoying it), my son keeps his reading skills going during the summer, and we enjoy a quiet activity together.