Organized and intentional suicide attacks during military conflicts

The Battle of the Long Sault

While the historiography gives many conflicting details and claims without sources (Some historians said...), I refer to the writings by contemporary witness Pierre-Esprit Radisson.

According to him the French settlements got intel from trappers, mountainman and friendly Indians that the Iroquois were preparing one massive assault on the french settlements which were allied with the Hurons and Algonquin. Approximately 1000 warriors were moving in to assault the settlements and burn them to the ground.

Adam Dollard des Ormeaux made the desperate decision to move against the Iroquois with only 17 of voluntary militia. He absolutely knew that it was a suicide mission, but he intended to inflict such heavy losses that the Iroquois would think twice to continue the attack on the settlements which had more weapons and men available. Every volunteer sweared to God that he would not give up and fight until the bitter end. For this reason Dollard had much more muskets and gunpowder than a normal hunting party and also grape shot. The allied Hurons were also an important factor that the numerical superiority was not so overwhelming.

The Wikipedia article is silent why such a small force was capable to hold off 200 Iroquois warriors for several days. The Iroquois were used to ambush the enemy party once they fired their muskets because the reloading time was slow. Their problem was that Dollard had three muskets available for each shooter and each shooter had one reloader who was reloading the muskets as fast as possible, so they were able to repel the attacks and inflict heavy losses. After a backup of 500 warriors arrived and started a human wave attack, the defenders switched to grapeshot and inflicted horrible losses.

While they finally succumbed, Dollard was successful: His strategy inflicted such losses that the Iroquois give up to attack the settlements.

In the struggle for the Pacific Islands, Japanese infantry launched nocturnal "Banzai" bayonet attacks on the Americans that were basically suicidal. http://en.wikipedia.org/wiki/Banzai_charge In the battle for Okinawa, the "superbattleship" Yamato was given enough fuel for a one-way trip (from Japan), and expected to sink as many American ships has possible, but not return. (She was sunk by American planes before reaching Okinawa.)

At the battle of Masada, the outnumbered and outweaponed Israeli defenders elected to follow a "scorched earth" policy, including taking each others' lives, rather than to surrender to the Romans. http://en.wikipedia.org/wiki/Battle_of_Masada

Shtrafbat were Soviet penal battalions used in the Eastern Front of World War II.

One form of Shtrafbat were tramplers. From Wikipedia:

Smaller battalions were established out of the infantry units to clear minefields as 'tramplers' - unarmed men who ran through the minefields ("trampled") ahead of regular assault forces to detonate land mines. The worst of all the penal battalion assignments, the tramplers were prepared for their grisly suicide missions by being heavily fortified with vodka rations by their leaders before attacks. Trampler battalions were assembled from the penal infantry units for major attacks and were usually wiped out to the last man, with their mangled bodies reportedly "marking the safe passage corridor of the late-war Red Army through any minefield".

Technically, tramplers weren't attacking the enemy, but they assisted others attacking the enemy.

A similar tactic was reportedly used by Iran in the Iran-Iraq war. Again, from Wikipedia

During the Iran-Iraq War hundreds of thousands volunteered for the Basij, including children as young as 12 and unemployed old men, some in their eighties. These volunteers were swept up in Shi'i love of martyrdom and the atmosphere of patriotism of the war mobilization. They were encouraged through visits to the schools and an intensive media campaign. The Basij may best be known for their employment human wave attacks which cleared minefields or draw the enemy's fire. It is estimated that tens of thousands were killed in the process. Some reports have the Basiji marching into battle marking their expected entry to heaven by wearing plastic "keys to paradise" around their necks.

It has been said that during the Iran/Iraq war, Iran organized corps of volunteers whose job was to walk through Iraqi minefields and essentially clear the mines with their own bodies.

I'm not entirely sure how well established that is. However, it is fairly well documented that Iran would organize human-wave attacks, which are by their nature essentially suicidal for all but a perhaps a lucky few of the participants.

Human wave attacks in general are not an uncommon tactic in warfare, though. The storming of the beaches in Normandy was essentially a suicidal endevor for the first wave of units off the boats. The same can easily be said for the Zulu attacks at Rourke's Drift, the North Vietnamese at Hill 488, the torpedo aircraft attacks on the Japanese fleet at Midway, or pretty much the first wave of any attack against any fortified position in history.