The makers of a new toy, Chalktrail, had us at “kids, wheels, chalk, fresh air and fun.” In other words, all the good things about childhood in summer time. Their creation, brilliant in its simplicity, is an easy-to-install, no-tools-required chalk holder that attaches to the back of a bicycle or scooter (below). As children ride, they create colorful lines on the pavement, then large patterns as they retrace their paths. Each chunk of non-toxic, washable chalk yields 1 1/2 miles of tarmac art. The bracket adjusts to wheel sizes ranging from 12 in. to 29 in., so grownups can join in, too. Chalktrail recently concluded a successful campaign on Kickstarter; check here for updates on availability.