Asterisms

Asterisms are sub- or supersets of constellations which build a constellation itself, or a group of stars, physically related or not. Best kown is the Big Dipper as a part of the Great Bear. But there are more than just this one. Below you find the:

Beehive	Located in the constellation Cancer. It is an open star cluster, which is also called Praesepe or M44 and faintly visible to the naked eye. With the stars gamma Can and delta Can it forms another asterisms called the Asses and the Manger.
Belt of Orion	is being formed by the stars delta Ori, epsilon Ori and zeta Ori; in Latin Amerika it is called the "Three Marys".
Bier	is being built by the four stars alpha UMa, beta UMa, gamma UMa and delta UMa.
Big Dipper	most famous asterism. Formed by the following Stars of the Great Bear alpha UMa, beta UMa, gamma UMa, delta UMa, epsilon UMa, zeta UMa and eta UMa, it is often called "Wain" (Wagon) or "Charles's Wain" because of its resemblance with it when the Dipper handle is thought to be the wagon tongue.
Bull of Poniatowski	A T-shaped asterism just east of gamma Oph; it is formed by the stars 66 Oph, 67 Oph, 68 Oph and 70 Oph
Circlet	the western fish; the circlet is formed by gamma Psc, b Psc, theta Psc, iota Psc, 19 Psc, lambda Psc and kappa Psc.
Coalsack	Actually this is not a true asterism, but a dark patch on the Milky Way, in the constellation Crux. By the African Bushmen it was called "Old Bag".
Frederick's Glory	is formed by iota And, kappa And, lambda And and psi And
Guardians of the Pole	just beta UMi and gamma UMi
Head of Cetus	presented by alpha Cet, gamma Cet, xi_2 Cet, mu Cet and lambda Cet
Heavenly G	nine bright stars forming a G-shaped group. Seven of these stars are of 1st magnitude. In order they are: Aldebaran (alpha Tau), Capella (alpha Aur), Castor (alpha Gem), Pollux (beta Gem), Procyon (alpha CMi), Sirius (alpha CMa), Rigel (beta Ori), Bellatrix (gamma Ori) and Betelgeuse (alpha Ori)
Hyades	open cluster; V-shaped group superposed on alpha Tau, gamma Tau, delta Tau and epsilon Tau
Hydra Head	build by delta Hya, epsilon Hya, zeta Hya, eta Hya, rho Hya and sigma Hya
Job's Coffin	formed by the four stars alpha Del, beta Del, gamma Del and delta Del
Keystone	is formed by the epsilon Her, zeta Her, eta Her and pi Her
Kids	are called epsilon Aur, zeta Aur and eta Aur
Lozenge	build by the four stars beta Dra, gamma Dra, xi Dra and nu Dra
Milk Dipper	The following five members of the constallation Sagittarius can be interpreted as an inverted dipper in the Milky Way: zeta Sgr, tau Sgr, sigma Sgr, phi Sgr and lambda Sgr. This asterism is also known as The Teapot.
Northern Cross	is formed by the leading stars of the constellation Cygnus: alpha Cyg, beta Cyg, gamma Cyg, delta Cyg and epsilon Cyg
Northern Fly	This is a small triangle over the rear of Aries
Pleiades	Located in the constellation Taurus. This open star cluster is one of the Messier objects, M45. It also known as Seven Sisters or, in Latin America the Seven Little Goats
Segment of Perseus	the stars eta Per, gamma Per, alpha Per, delta Per, epsilon Per and zeta Per forming an arc.
Sickle	formed by alpha Leo, eta Leo, gamma Leo, zeta Leo, mu Leo and epsilon Leo
Square of Pegasus	At the edges of that square you find alpa Peg, beta Peg, gamma Peg and alpha And
Sword of Orion	theta Ori and iota Ori; between them the famous Orion Nebula (M42) is located.
Venus Mirror	also on Orion; the belt stars (delta Ori, epsilon Ori and zeta Ori), the sword and eta Ori build up this asterism. The sword forms the handle of the diamond-shaped mirror.
Y of Aquarius	also called Water Jar; the Y is build by gamma Aqr, eta Aqr, pi Aqr and zeta Aqr