The most popular coin in a different shape is a the 25p triangular coin by Isle of Man produced to commemorate the 2007/2008 Tutankhamun exhibition and became legal tender on 6 December 2007. Other triangular coins issued earlier include: Cabinda coin, Bermuda coin, 2 Dollar Cook Islands 1992 triangular coin, Uganda Millennium Coin and Polish Sterling-Silver 10-Zloty Coin. Guitar-shaped coins were once issued in Somalia, Poland once issued a fan-shaped 10 złoty coin, but perhaps the oddest coin ever was the 2002 $10 coin from Nauru, a Europe shaped coin. Almost all those coin is not a circulation coin and sell at a high price.
This triangular coin is 2002 Cook Islands 2 dollars. The coin is made from copper nickel with 28.52 mm in diameter. On the obverse is the face of Queen Elizabeth II head facing right, date below and on the reverse kumete table, morter and pestle from Atiu Island, denomination above. The Cook Islands are in the South Pacific Ocean, north-east of New Zealand, between French Polynesia and American Samoa. Cook Islands consist of fifteen major islands, spread over 2.2 million square kilometres of ocean, divided into two distinct groups: the Southern Cook Islands, and the Northern Cook Islands of coral atolls. The islands were formed by volcanic activity; the northern group is older and consists of six atolls (sunken volcanoes topped by coral growth). The dollar has been the currency of the Cook Islands since 1967. Before that, Cook Island using Pound as a monetary currency. The dollar is subdivided into 100 cents, although some 50 cent coins carry the denomination as "50 tene". The Cook Islands dollar is pegged at par to the New Zealand dollar.
This center hole coin is Belgium 10 centimes. The coin is made from Copper-Nickel and 22 mm in diameter. On the obverse is center hole within crowned monogram, date below, legend in French (BELGIQUE) and on the reverse is spray of leaves to left of center hole, denomination to right. The franc (Dutch: frank, French: franc, German: Franken) was the currency of Belgium until 2002 when the euro was introduced into circulation. It was subdivided into 100 centiem (Dutch), centimes (French) or Centime (German). The conquest of most of western Europe by revolutionary and Napoleonic France led to the French franc's wide circulation. In the Austrian Netherlands (now Belgium), the franc replaced the kronenthaler. This was in turn replaced by the Dutch gulden when the Kingdom of the Netherlands was formed.Following independence from the Kingdom of the Netherlands, the new Kingdom of Belgium in 1832 adopted its own franc, equivalent to the French franc, followed by Luxembourg in 1848 and Switzerland in 1850. Newly-unified Italy adopted the lira on a similar basis in 1862.Like 10 other European currencies, the Belgian/Luxembourgish franc ceased to exist in January 1, 1999. Old franc coins and notes lost their legal tender status in February 28, 2002.
This is Hong kong 2 dollar coin. Its made of Copper-Nickel, weight at 8.40 gm and 28 mm in diameter. On the obverse is Bauhinia flower with large numeral Denomination on the reverse.The coin edge is scalloped. The Hong Kong coinage, including 10¢, 20¢, 50¢, $1, $2, $5 & $10, is issued by Hong Kong Monetary Authority on behalf of the Government of Hong Kong. Until 1992 these coins were embossed with the British monarch's effigy. From January 1993 to November 1994, a new series depicting the bauhinia flower was gradually issued, including a new denomination $10. Since the beginning of the coin replacement programme in 1993, over 585 million Queen's effigy coins have been withdrawn from circulation. However, the Queen's Head coins remain legal tender.
This is British Malaya half cent rectangle coin. On the obverse is crowned head of King George VI facing left and on the reverse is its value within beaded circle. British Malaya loosely described a set of states on the Malay Peninsula that were colonized by the British from the 18th and the 19th until the 20th century. Before the formation of Malayan Union in 1946, the colonies were not placed under a single unified administration. Instead, British Malaya comprised the Straits Settlements, the Federated Malay States and the Unfederated Malay States. Malaya was the world's largest producer of tin and later rubber. Malayan Union was dissolved and replaced with Federation of Malaya in 1948. It became independent on 31 August 1957. On 16 September 1963, the federation, along with Sabah, Sarawak and Singapore formed a larger federation called Malaysia.
You can find other different shape coins in most Malaysia Coin Dealer shop. For a start, you don't need to buy for them a high grade coins, coin in a Very Fine condition should be OK. Teach them to collect and inspire them to search for the coin information.
Source: Wikipedia, search.com, Krause Publication