Ok, based on most textbook teachings there were only 9 officially recognized crusades, (and that's being generous - with the textbooks) but weren't there really something more like 12 or more?
First Crusade 1096-1099
Pope Urban II called upon all Christians to join a war against the Turks in response to Alexis I request for help defending against the invading Seljuk Turks.
Crusade of 1101
(No information available on this crusade.)
Second Crusade 1147-1148
After a period of relative peace Muslims conquered the town of Edessa. A new crusade was called for by various preachers, most notably by Bernard of Clairvaux. French and German armies, under the Kings Louis VII and Conrad III respectively, marched to Jerusalem in 1147 but failed to accomplish any major successes, and indeed endangered the survival of the Crusader states with a strategically foolish attack on Damascus.
Third Crusade 1189-1192
In 1187, Saladin, Sultan of Egypt, recaptured Jerusalem. Pope Gregory VIII called for a crusade, which was led by several of Europe's most important leaders: Philip II of France, Richard I of England (aka Richard the Lion Heart) and Frederick I, Holy Roman Emperor.
Fourth Crusade 1200-1204
The Fourth Crusade was initiated in 1202 by Pope Innocent III, with the intention of invading the Holy Land through Egypt. Because the Crusaders lacked the funds to pay for the fleet and provisions that they had contracted from the Venetians, Doge Enrico Dandolo, enlisted them to restore to obedience the Christian city of Zara (Zadar). Because they subsequently lacked provisions and time on their vessel lease the leaders decided to go to Constantinople, where they attempted to place a Byzantine exile on the throne. After a series of misunderstandings and outbreaks of violence, the crusaders sacked the city in 1204.
Albigensian Crusade 1209
The Albigensian Crusade was launched in 1209 to eliminate the heretical Cathars of Occitania (the south of modern-day France). It was a decades-long struggle that had much more to do with the concerns of northern France to extend its control southwards than it did with heresy. In the end, both the Cathars and the independence of southern France were exterminated.
Children's Crusade 1212
The Children's Crusade is a series of possibly fictitious or misinterpreted events of 1212. You can read the ridiculous story by searching for the name of the crusade on most any search engine.
Fifth Crusade 1217-1221
By processions, prayers, and preaching, the Church attempted to set another crusade on foot, and the Fourth Council of the Lateran (1215) formulated a plan for the recovery of the Holy Land. In the first phase, a crusading force from Hungary, Austria joined the forces of the king of Jerusalem and the prince of Antioch to take back Jerusalem. In the second phase, crusader forces achieved a remarkable feat in the capture of Damietta in Egypt in 1219, but under the urgent insistence of the papal legate, Pelagius, they proceeded to a foolhardy attack on Cairo, and an inundation of the Nile compelled them to choose between surrender and destruction.
Sixth Crusade 1228-1229
Emperor Frederick II had repeatedly vowed a crusade but failed to live up to his words, for which he was excommunicated by Pope Gregory IX in 1228. He nonetheless set sail from Brindisi, landed in Palestine, and through diplomacy he achieved unexpected success: Jerusalem, Nazareth, and Bethlehem were delivered to the crusaders for a period of ten years.
Seventh Crusade 1248-1254
The papal interests represented by the Templars brought on a conflict with Egypt in 1243, and in the following year a Khwarezmian force summoned by the latter stormed Jerusalem. The crusaders were drawn into battle at La Forbie in Gaza. The crusader army and its Bedouin mercenaries were outnumbered by Baibars' force of Khwarezmian tribesmen and were completely defeated within forty-eight hours. This battle is considered by many historians to have been the death knell to the Kingdom of Outremer.
Eighth Crusade 1270
The eighth Crusade was organized by Louis IX in 1270, again sailing from Aigues-Mortes, initially to come to the aid of the remnants of the crusader states in Syria. However, the crusade was diverted to Tunis, where Louis spent only two months before dying.
Ninth Crusade 1271-1272
The future Edward I of England undertook another expedition in 1271, after having accompanied Louis on the Eighth Crusade. He accomplished very little in Syria and retired the following year after a truce. With the fall of Antioch (1268), Tripoli (1289), and Acre (1291), the last traces of the Christian rule in Syria disappeared.
Northern Crusades (Baltic and Germany)
The Crusades in the Baltic Sea area and in Central Europe were efforts by (mostly German) Christians to subjugate and convert the peoples of these areas to Christianity. These Crusades ranged from the 12th century, contemporaneous with the Second Crusade, to the 16th century.
I know there were more, but this is all I have and what are considered to be the "Official" crusades. Though the Northern Crusades were added only because it is probably the only one where an attempt was made to convert the indigenous people into Christianity, all others that I am aware of were attempt to regain lands from the Muslims who had taken them by force.

