SHEVAT:
15 - Tu B’shevat (Fifteenth of Shevat)
ADAR:
14 - Purim
NISAN:
15-21 – Passover
IYAR:
Counting the Omer
SIVAN:
6-7 - Shavout
TAMMUZ:
Tu B'Shevat
On the first of Shevat is the New Year for the tree; this ruling is in accordance with the statement of Beit Shammai. But Beit Hillel say: The New Year for trees is on the fifteenth of Shevat.
(18) She is a tree of life to them that lay hold upon her, And happy are all that hold on to her.
Purim
§ The mishna teaches that from when the month of Av begins, one decreases acts of rejoicing. Rav Yehuda, son of Rav Shmuel bar Sheilat, said in the name of Rav: Just as when Av begins one decreases rejoicing, so too when the month of Adar begins, one increases rejoicing.
The Four Mitzvot of Purim
Megillah Reading - Book of Esther – The Megillah is read twice on Purim, once at night and once during the day. In order to properly fulfill the mitzvah of Megillah, it is necessary to hear every word during the reading. For this reason it is imperative that people not talk to each other during the Megillah reading.
Mishloach Manot/Shalach Manos - Sending Gifts – Every Jew is obligated to give at least one Mishloach Manot gift containing at least two different types of ready-to-eat food items.
Matanot La'evyonim - Gifts to the Poor – Giving to the poor is a mitzvah all year round. However, the mitzvah to do so on Purim is in addition to the general mitzvah of tzedakah (charity). To properly fulfill the mitzvah of Matanot La'evyonim one must give to two poor individuals. Although one may fulfill this mitzvah by giving a very minimal amount of money to each person, the sages noted that the highest form of fulfilling this mitzvah is by giving enough money for a meal, or the equivalent in food. This mitzvah may be fulfilled by donating beforehand to an organization that will distribute the money or food on Purim day.
Seudah - Festive Meal – One is obligated to partake in a festive meal on Purim day. The bare minimum to fulfill this mitzvah requires that one ritually wash (netillat yadayim), eat bread and then recite the Birkat Hamazon , the Grace after Meals.
Drinking at the Purim Meal – "A person should drink on Purim up to the point where they cannot tell the difference between ‘Blessed is Mordechai' and ‘Cursed is Haman.' (Talmud Megillah 7a and Shulchan Aruch --Code of Jewish Law). On Purim, one is commanded to drink wine to a point of inebriation* – generally, this is interpreted as drinking more than one usually would or enough to make one sleepy.
From jewishtreats.org
Whoever enters Adar -- These were days of miracles for Klal Yisrael, specifically Purim and Pesach.
Passover
מַעֲשֶׂה בְּרַבִּי אֱלִיעֶזֶר וְרַבִּי יְהוֹשֻׁעַ וְרַבִּי אֶלְעָזָר בֶּן-עֲזַרְיָה וְרַבִּי עֲקִיבָא וְרַבִּי טַרְפוֹן שֶׁהָיוּ מְסֻבִּין בִּבְנֵי-בְרַק וְהָיוּ מְסַפְּרִים בִּיצִיאַת מִצְרַיִם כָּל-אוֹתוֹ הַלַּיְלָה, עַד שֶׁבָּאוּ תַלְמִידֵיהֶם וְאָמְרוּ לָהֶם רַבּוֹתֵינוּ הִגִּיעַ זְמַן קְרִיאַת שְׁמַע שֶׁל שַׁחֲרִית.
It happened once [on Pesach] that Rabbi Eliezer, Rabbi Yehoshua, Rabbi Elazar ben Azariah, Rabbi Akiva and Rabbi Tarfon were reclining in Bnei Brak and were telling the story of the exodus from Egypt that whole night, until their students came and said to them, "The time of [reciting] the morning Shema has arrived."
Maimonides (Rambam) Laws of Leavened and Unleavened Bread 7:6
"In every generation, a person is obligated to show him or herself as though s/he came forth from Egypt."
Counting the Omer
And from the day on which you bring the sheaf of elevation offering—the day after the sabbath—you shall count off seven weeks. They must be complete: you must count until the day after the seventh week—fifty days; then you shall bring an offering of new grain to God. You shall bring from your settlements two loaves of bread as an elevation offering; each shall be made of two-tenths of a measure of choice flour, baked after leavening, as first fruits to God.
Shavout
(3) And Moses went up unto God, and the LORD called unto him out of the mountain, saying: ‘Thus shalt thou say to the house of Jacob, and tell the children of Israel:
(טו) וְכָל־הָעָם֩ רֹאִ֨ים אֶת־הַקּוֹלֹ֜ת וְאֶת־הַלַּפִּידִ֗ם וְאֵת֙ ק֣וֹל הַשֹּׁפָ֔ר וְאֶת־הָהָ֖ר עָשֵׁ֑ן וַיַּ֤רְא הָעָם֙ וַיָּנֻ֔עוּ וַיַּֽעַמְד֖וּ מֵֽרָחֹֽק׃
(ט) אַתֶּ֨ם נִצָּבִ֤ים הַיּוֹם֙ כֻּלְּכֶ֔ם לִפְנֵ֖י יְהוָ֣ה אֱלֹהֵיכֶ֑ם רָאשֵׁיכֶ֣ם שִׁבְטֵיכֶ֗ם זִקְנֵיכֶם֙ וְשֹׁ֣טְרֵיכֶ֔ם כֹּ֖ל אִ֥ישׁ יִשְׂרָאֵֽל׃ (י) טַפְּכֶ֣ם נְשֵׁיכֶ֔ם וְגֵ֣רְךָ֔ אֲשֶׁ֖ר בְּקֶ֣רֶב מַחֲנֶ֑יךָ מֵחֹטֵ֣ב עֵצֶ֔יךָ עַ֖ד שֹׁאֵ֥ב מֵימֶֽיךָ׃ (יא) לְעָבְרְךָ֗ בִּבְרִ֛ית יְהוָ֥ה אֱלֹהֶ֖יךָ וּבְאָלָת֑וֹ אֲשֶׁר֙ יְהוָ֣ה אֱלֹהֶ֔יךָ כֹּרֵ֥ת עִמְּךָ֖ הַיּֽוֹם׃ (יב) לְמַ֣עַן הָקִֽים־אֹתְךָ֩ הַיּ֨וֹם ׀ ל֜וֹ לְעָ֗ם וְה֤וּא יִֽהְיֶה־לְּךָ֙ לֵֽאלֹהִ֔ים כַּאֲשֶׁ֖ר דִּבֶּר־לָ֑ךְ וְכַאֲשֶׁ֤ר נִשְׁבַּע֙ לַאֲבֹתֶ֔יךָ לְאַבְרָהָ֥ם לְיִצְחָ֖ק וּֽלְיַעֲקֹֽב׃ (יג) וְלֹ֥א אִתְּכֶ֖ם לְבַדְּכֶ֑ם אָנֹכִ֗י כֹּרֵת֙ אֶת־הַבְּרִ֣ית הַזֹּ֔את וְאֶת־הָאָלָ֖ה הַזֹּֽאת׃ (יד) כִּי֩ אֶת־אֲשֶׁ֨ר יֶשְׁנ֜וֹ פֹּ֗ה עִמָּ֙נוּ֙ עֹמֵ֣ד הַיּ֔וֹם לִפְנֵ֖י יְהוָ֣ה אֱלֹהֵ֑ינוּ וְאֵ֨ת אֲשֶׁ֥ר אֵינֶ֛נּוּ פֹּ֖ה עִמָּ֥נוּ הַיּֽוֹם׃
(9)You stand this day, all of you, before the Lord your God—your tribal heads, your elders and your officials, all the men of Israel, (10)your children, your wives, even the stranger within your camp, from woodchopper to waterdrawer— (11)to enter into the covenant of the Lord your God, which the Lord your God is concluding with you this day, with its sanctions; (12)to the end that He may establish you this day as His people and be your God, as He promised you and as He swore to your fathers, Abraham, Isaac, and Jacob.(13)I make this covenant, with its sanctions, not with you alone, (14)but both with those who are standing here with us this day before the Lord our God and with those who are not with us here this day.
Shemot Rabbah 5:9
Rabbi Yochanan said the voice of God went forth and was split into 70 voices, 70 languages, so that all the nations would hear, and each nation would hear the voice in its own tongue...The voice of God spoke to each Israelites, that means to each and every person. God's voice was heard and understood because the voice spoke to each individual according to that person's particular ability to hear and understand...to the elderly in keeping with their ability, to the young in keeping with their ability, to the little ones in keeping with their ability, and so on.
SHEVAT:
15 - Tu B’shevat (Fifteenth of Shevat)
ADAR:
14 - Purim
NISAN:
15-21 – Passover
IYAR:
Counting the Omer
SIVAN:
6-7 - Shavout