Lag Ba'Omer: Should I go to the Hillula?

(15) And ye shall count unto you from the morrow after the day of rest, from the day that ye brought the sheaf of the waving; seven weeks shall there be complete; (16) even unto the morrow after the seventh week shall ye number fifty days; and ye shall present a new meal-offering unto the LORD.

They said That Rabbi Akiva had twelve thousand pairs of disciples, from Gabbat to Antifaras; and they all died at the same time because they did not treat each other with respect. The world remained desolate until Rabbi Akiva came to our Masters in the South and taught the Torah to them, and it was they who revived the Torah at that time. These were Rabbi Meir, Rabbi Judah, Rabbi Yossi, Rabbi Shimon and Rabbi Eleazar ben Shammua; And it was they who revived the Torah at that time. A Tanna taught: All of them died between Passover and Pentecost.

(1) It is customary not to get married between Pesach and Shavuot, until Lag BaOmer (the 33rd day), because during that time, the students of Rabbi Akiva died. However, to do "erusin" and "kiddushin" (engagement and betrothal) is OK. And even for "nisuin" (marriage), if someone did so, we do not punish him. Rema: however, from Lag Ba'Omer onwards, all this is permitted (Abudraham, Beit Yosef & Minhagim).

(2) It is customary not to cut one's hair until Lag BaOmer, since it is said that that is when they stopped dying. One should not cut one's hair until the 34th day, in the morning, unless the 33rd day falls on Friday, in which case one may cut one's hair then, in honor of the Sabbath ("kavod Shabbat"). Rema: But in these countries, we do not follow the custom he advocates; rather, we cut our hair on the 33rd day, and we rejoice a bit, and we do not say Tachanun (Maharil and Minhagim). And one should only cut one's hair on the 33rd day itself, but not on its evening. However, if it falls on Sunday, our custom is to cut our hair on Friday in honor of the Sabbath (Maharil). Someone who is performing a brit milah (i.e., the sandak, mohel and the infant's father), or circumcizing his son, is allowed to cut his hair during sefirah in honor of the circumcision (Hagahot Minhagim).

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For R. Judah, R. Jose, and R. Simeon were sitting, and Judah, a son of proselytes, was sitting near them. R. Judah commenced [the discussion] by observing, ‘How fine are the works of this people! They have made streets, they have built bridges, they have erected baths.’ R. Jose was silent. R. Simeon b. Yohai answered and said, ‘All that they made they made for themselves; they built market-places, to set harlots in them; baths, to rejuvenate themselves; bridges, to levy tolls for them.’ Now, Judah the son of proselytes went and related their talk, which reached the government. They decreed: Judah, who exalted [us], shall be exalted, Jose, who was silent, shall be exiled to Sepphoris; Simeon, who censured, let him be executed. He and his son went and hid themselves in the Beth Hamidrash,[and] his wife brought him bread and a mug of water and they dined. [But] when the decree became more severe be said to his son, Women are of unstable temperament: she may be put to the torture and expose us.’So they went and hid in a cave.

A miracle occurred and a carob-tree and a water well were created for them. They would strip their garments and sit up to their necks in sand. The whole day they studied; when it was time for prayers they robed, covered themselves, prayed, and then put off their garments again, so that they should not wear out. Thus they dwelt twelve years in the cave. Then Elijah came and stood at the entrance to the cave and exclaimed, Who will inform the son of Yohai that the emperor is dead and his decree annulled? So they emerged. Seeing a man ploughing and sowing, they exclaimed, ‘They forsake life eternal and engage in life temporal!’ Whatever they cast their eyes upon was immediately burnt up. Thereupon a Heavenly Echo came forth and cried out, ‘Have ye emerged to destroy My world: Return to your cave! So they returned and dwelt there twelve months, saying, ‘The punishment of the wicked in Gehenna is [limited to] twelve months.’A Heavenly Echo then came forth and said, ‘Go forth from your cave!’

Rabbi Shimon's Change of Perspective:

On the eve of the Sabbath before sunset they saw an old man holding two bundles of myrtle and running at twilight. What are these for?’ they asked him. ‘They are in honour of the Sabbath,’ he replied. ‘But one should suffice you’?-One is for ‘Remember-’ and one for ‘Observe.’Said he to his son, ‘See how precious are the commandments to Israel.’ Thereat their minds were tranquilized...

Since a miracle has occurred, said he, let me go and amend something... Rab said: He instituted coinage for them. Samuel said: He instituted markets for them; R. Johanan said: He instituted baths for them.

Truculent stingers and shield-bearing warriors from Sepphoris came and beset them. The people of Meron banded together and shouted, for they feared he would not be buried there. After the bed emerged from the house, it rose into the air; fire blazed before it. They heard a voice: “Come and enter! Assemble for the wedding celebration of Rabbi Shim'on!"

Zohar: The Book of Enlightenment, Translated by Daniel Matt, p. 188

For the Leader; upon the Gittith. A Psalm of the sons of Korah.

How lovely are Thy tabernacles, O LORD of hosts!

My soul yearneth, yea, even pineth for the courts of the LORD; my heart and my flesh sing for joy unto the living God.