Easy and fun.Velcro + popsicle sticks make for great quiet time or restaurant activity. Put velcro dots on the ends of popsicle sticks. Kids can make letters or shapes over and over again. I found velcro dots at my local dollar store.
DIY Sand and Rock Box by FSPDT. Gdjk -> made this with toilet rolls (aka tunnels) and moon sand instead of play sand. My son loved playing with it. The moon sand cleans up nicely indoors but play sand will be easier to play with when using the small cars.