Keep the kids entertained this week with these free and cheap ideas.

Monday: Where's Waldo scavenger hunt. Go to Antigone Books, 411 N. Fourth Ave., the children's section of the Joel Valdez Main Library, 101 N. Stone, or Yikes Toys, 2930 E. Broadway, and pick up a passport for the contest. Then try and find at least 20 of the 26 Waldos to be entered in a raffle to win Waldo prizes and prizes donated by participating businesses. Each time you find a Waldo, you'll get a stamp. Turn in the passport by July 31. All Waldo spotters who turn in their passports will be invited to attend a Waldo party at Antigone Books on August 4. It's free to participate.

Tuesday: Optical Illusions at Murphy-Wilmot Library, 530 N. Wilmot Road. Kids in sixth to eighth grade will explore geometric shapes, line and movement, color and creating designs. Presented by TeenzArt. 2 p.m. Free.

Wednesday: Summer Preschool Story time at the Sabino Canyon Visitor Center, 5700 N. Sabino Canyon Road. Stories, puppets, games, crafts and activities related to a weekly theme and presented by a volunteer naturalist. Event is for accompanied children age 4 to 7. Attendees park free with pass from visitor center. 9 a.m. Free.

Thursday: Juggling workshop at Wheeler Taft Abbett Senior Library, 7800 N. Schisler Drive. Kids ages 12 and up can learn to juggle with James Reid. Call 594-5200 to register. 4 p.m. Free.

Friday: Lizard Walk at Agua Caliente Park, 12325 E. Roger Road. Guided walk to find whiptail, spiny, ornate tree and other lizards that roam the park. Binoculars available or bring your own. 7:30 a.m. Free.

Saturday: 2nd Saturdays Downtown, Congress Street from Toole Ave. to Church Ave. Local performers, artisans and food. Kids area at Old Pueblo parking lot on Congress, east of Stone includes a movie and popcorn, virtual reality and a jumping castle. 6 to 11 p.m. Free.

Sunday: Science Sunday at Children's Museum Tucson, 200 S. Sixth Ave. Hands on science related activities for kids and families presented by a guest partner. 10 a.m. to 5 p.m. $2.