The Concise Oxford Dictionary actually lists the origin of "punch" in this sense as "17th c.; orig. unkn.", but this charming version is often encountered and may even be true:
Punch (drink)
http://en.wikipedia.org/wiki/Punch_(drink)
Some old (1950s and '60s) recipes from my parents:Punch is the term for a wide assortment of drinks, both non-alcoholic and alcoholic, generally containing fruit or fruit juice. The drink was introduced from India to England in the early seventeenth century; from there its use spread to other countries. Punch is typically served at parties in large, wide bowls, known as punch bowls.
History
The word punch is a loanword from Hindi panch (meaning five) and the drink was originally made with five ingredients: alcohol, sugar, lemon, water, and tea or spices. The original drink was named paantsch.
The drink was brought to England from India by sailors and employees of the British East India Company in the early seventeenth century. From there it was introduced into other European countries. When served communally, the drink is expected to be of a lower alcohol content than a typical cocktail.
The term punch was first recorded in British documents in 1632. At the time, most punches were of the Wassail type made with a wine or brandy base. But around 1655, Jamaican rum came into use and the 'modern' punch was born. By 1671, documents make references to punch houses....
Rum Punch
1½ 25 oz. bottle Maraca Rum
1½ 30 oz. bottle ginger ale
Juice of 12 oranges (approx. 20 ozs.)
6 oz. pineapple juice
¾ cup powdered sugar
Stir gently. Pour over a block of ice in a large bowl.
Rye Punch
1½ 25 oz. bottles rye whisky
1 30 oz. bottle ginger ale
1 30 oz. bottle soda water
Juice of 12 oranges (approx. 20 ozs.)
Juice of 6 lemons (approx. 10 ozs.)
1 cup brown sugar
Pour into large bowl and add lumps of ice. Add 1 dozen slices of oranges and 4 slices of quartered pineapple. Stir gently and serve.
Gin Punch
2 25 oz. bottles Crystal Gin
⅓ cup fruit sugar
18 ozs. orange juice
4 ozs. lemon juice
6 ozs. pineapple juice
1 30 oz. bottle Tom Collins mix
1 30 oz. bottle soda water
Pour over block of ice in large punch bowl. Garnish with slices of orange and lemon.
EDIT:
12 party punch recipes
Top 20 punch recipes - Allrecipes.com