If you're devoted to explosions, and who isn't, you'll love the new expanded 2nd edition of William Gurstelle's Backyard Ballistics, now 25% longer, with 25% more ka-boomery. Still the go-to reference work for building rockets, cannons (carbide and potato), flingers, fire kites, electromagnetic pipe guns, tennis ball mortars, cleaner-bag balloons, ballistic pendula and petards. You simply can't have more fun with common household materials. The soft-cover, 210pp compendium includes detailed and illustrated instructions, parts lists and sensible ways not to be hoist on your own petard. Be careful out there.

Make a whole bunch of fun and instructive Lego® machines/chain reaction models like marble runs and mousetraps involving ramps, buckets, funnels balances and much more. Comes with (33) Lego® elements, (6) Lego® balls, a dozen paper props, and a 78-page instruction booklet for (10) machines. You add a few common household items. Includes suggestions for more complicated devices if you have your own Lego® pieces, and if you don't, what are you waiting for? Ages 8+.

50 Science Things to Make and Do is just that, a passel of experiments, all illustratively explained in two facing pages of this big 104-page flip book, and all easily done with common household items. Includes wind and water power, bugs, crystals, paper planes, rubber-band guitars, balances, gloop, optics and a ton of other fun, informative stuff. Officially classified as "cool" by several of our geekiest staffers.

Why does it do that? Develop an elemental understanding of magnetism, electromagnetism, electrochemistry, radio, thermodynamics, light and optics. Simon Quellen Field's 228-page paperback, Gonzo Gizmos, Projects & Devices to Channel your Inner Geek explains processes, equipment and scientific terms -- and then, for starters, tells you things like how to make a rotary steam engine in 15 minutes from a soda can, a candle and a few scraps of rubber tubing. It's the favorite of our resident geeks -- but not for kids unless they're working with an adult. That would be a mature adult. An insured, mature adult.

A must-have for micro-warriors; Mini Weapons of Mass Destruction by John Austin (author of the best-selling Cubicle Warfare) is 241 pages of detailed instructions for building (42) implements of spitball warfare from ordinary household objects and office supplies. With the caveat that this is written for responsible individuals who take reasonable safety precautions (don't do anything your mother would scream at) we have to say that we love the binder-clip crossbow and the tongue-depressor catapult. Volume 2, which is 251 pages, has a secret-agent flair with new gadgets like the push-pin dart, toothpaste periscope and cereal briefcase. 

Very popular with elementary school teachers, these hardcover blank books let students create their own storybooks. (Middle-schoolers interviewing and making books for primary grade kids is a popular and civilizing project.) Also great for sketching, journaling or scrapbooking. Pure white blank covers with (14) sheets (28 pages) of 80-lb blank paper inside with a sewn-in binding. You pick the 6” x 8” books or the 8-1/2” x 11” versions.