| AstroWeb Astronomical internet resources from the National Radio Astronomy Observatory. |
| An_Atlas_of_the_Universe Contains 3D maps of the universe zooming out from the nearest stars to the scale of the galaxy and out to the surrounding superclusters and finally to the scale of the known universe. |
| Beyond_Earth_-_Everything_Not_on_Earth Provides information about the beginning of universe and solar system. About the planets, quasars, the Milky Way, black holes. Life of a star. Travel in space and extra terrestrial beings. |
| Eric_Weisstein\'s_World_of_Astronomy A web encyclopedia. Over 500 entries, ranging from definitions to full articles. |
| Infrared_Astronomy All about infrared astronomy from NASA's infrared astronomy center: Discovery of infrared, what is infrared and infrared astronomy, history, the infrared universe, gallery, activities, discoverie |
| Logarithmic_Maps_of_the_Universe Show universe in terms of distance from Earth center. Includes such things as satellites, planets, stars, nebulae, and galaxies, out to cosmic microwave background radiation from the Big Bang. |
| The_Naming_of_Stars Leaflet from Royal Greenwich Observatory. |
| Space_com_-_The_Greatest_Myths,_Hoaxes_&_Mysteries_in_Astronomy_and_Space_Science Article briefly discussing 21 topics. |
| Stars_and_Planets Information about interesting stars and planets in our galaxy, as well as astral bodies outside the Milky Way. Includes photos. |
| Planetary_Phenomena Historical account of conjunctions, occultations, and transits 3000 BC to 3000 AD. |
| Air_Movement_and_Control_Association Provides publications, membership, certified ratings program and seminars for manufacturers of air system equipment including fans, louvers, dampers, air curtains, airflow measurement stations, and ac |
| Chartered_Institution_of_Building_Services_Engineers_(CIBSE) UK-based institution for building services including heating, ventilation and air conditioning. |
| Cooling_Technology_Institute Nonprofit self-governing technical association dedicated to improvement in technology, design, performance and maintenance of cooling towers. Membership, publications, certification, and meetings. |
| Eastern_Michigan_ASHRAE Newsletter, calendar of events and the contact to the society's officers. |
| South_African_Institute_of_Refrigeration_&_Air_Conditioning Site gives details about the organisation including training courses, journals and data manuals. |
| The_Wichita_Chapter_of_ASHRAE This site describes the activities of the Wichita, Kansas chapter of the ASHRAE. |
| University_of_Illinois_at_Urbana-Champaign Student chapter overview, news, event and activity information, design projects, member resumes, officer list, mailing list, and membership information. |
| The_Aesthetics_of_Symmetry A brief digression into how people perceive symmetrical patterns -- what makes them boring, interesting, or overly intricate |
| Back_to_Square_One Includes description, solutions and other resources on this cube-like puzzle. |
| Critical_Math Articles and images on recreational math from fractals and magic squares to mathemorchids and Galois. |
| Cryptarithms_Online 70 brain-teasers; a Primer on Cryptarithmetic; books and links to alphametics on the Web. |
| CuriousMath Include news, math tricks, methods, facts, trivia, mostly posted by users. |
| David_Singmaster__List_of_Available_Material Teaching and recreational items in this personal collection. |
| The_Diamond_16_Puzzle New version of the classic puzzle using row/column/quadrant permutations to display symmetries of graphic designs. Has link to a site on the underlying mathematics (Diamond Theory). |
| A_Disproof_of_Pythagoras\'_Theorem? A method of disproving the Theorem of Pythagoras is presented. The author is adamant that this is intended only as a puzzle to find the mistake in the arguments, and not as a serious proposal. |
| The_Eugène_Strens_Recreational_Mathematics_Collection A special collection at the University of Calgary, including the archives of Martin Gardner. There is a searchable online index. |
| Eureka The annual journal of the Archimedeans, the mathematical society of the University of Cambridge. It regularly contains articles on recreational mathematics. |
| Fair_Dice Contains a complete list of all possible Fair Dice, most of which are not cubes. Includes pictures. |
| Famous_Curves Visual animations of famous curves. |
| Fast_Arithmetic_Tips Three categories: defensive - know to check an answer, offensive - fast mental calculations, and math magic. |
| Fibonacci_numbers_and_the_Pascal_triangle The relation between Fibonacci numbers and Pascal's triangle. English/German/Serbian. |
| Final_Answers Numerous facts including formulas, magic tricks, fallacies, recreations compiled by Dr. Gerald P. Michon. |
| Fun_With_Mathematics Includes pages on the topics of primes, fibonacci numbers, PI computation, data encryption and links to calculator programs. |
| Gardner_Index Rough index to the fifteen books containing Martin Gardner's Mathematical Games articles from Scientific American. |
| Geometric_Packing_Problems By Joseph Malkevitch: "Given one shape X how and when can one pack identical copies of this shape into another shape Y?" |
| HAKMEM A collection of problems from MIT. Work reported herein was conducted at the Artificial Intelligence Laboratory, a Massachusetts Institute of Technology research program. |
| How_To_Manually_Find_A_Square_Root The way to do find a square root without a calculator. |
| Iamond A page on polyiamond puzzles. Includes many pages on tessellation. |
| Jlpe\'s_Number_Recreations_Page Features original number recreations by the author, such as generalized perfect numbers, digital diversions, diophantine equations, didactic numbers, and number theory. |
| Look_and_Say_Sequence_Generator Creates a special kind of summation formula created by John Conway. |