David A. Carter and Noelle Carter's Bot Garage (Random House/Smashing Ideas, 2011), a companion to their 2011 counting pop-up book Lots of Bots, invites users to recreate the wacky robots showcased in the book and create their own inventions.

Build a robot by selecting from a gallery of ten brightly colored options for each bot part: torso, head, arms, and "legs" (some of which are actually wheels or rocket blasters). Then "add some flair" with spare parts such as a robot dog, microphone, clock, and bicycle horn. All of the parts differ in design and function, illustrated by a brief animation, so the combinations are virtually endless.

When your bot is built, give it a name and place it in one of ten environments such as undersea, tropical island, space, and disco dance floor (fans of Lots of Bots will recognize the scenery). Once situated, the bot will then come to life, happily bouncing, beeping, sproinging, and whirring away indefinitely. All the bots you've created can be saved to revisit — even rebuild — later, or emailed to a friend.

The uncredited child narrator reading the text's sing-songy rhymed couplets ("We'll need a head to go on top, so go, go, go. No time to stop!") is overly cutesy for my taste, but kids will be too focused on the robots to pay him much mind. With its quirky bots, fun sound effects, clear instructions, and simple navigation, this app will hold up for several play-throughs.

Available for iPhone, iPad, and iPod Touch (requires iOS 5.0 or later); $0.99. Recommended for preschool users.