What Happens if You Leave Your Sefer Open?

In the sefer "Kitzur Shala"h," the author brings the following story:
"A certain scribe completed his work for the night and left the scroll open to the verse [that he had just finished writing] '...and the goats will dance there.' (ישעיה יג, כא) Upon arising early the next morning before daybreak, he encountered a demon sitting on his chair. The demon told him 'know that I am the demon named שד - the Guardian of the Pages and I have come to harm you. Yet, I will forgive you for I heard during the ten days of penitence that I do not have permission to harm you. Instead, accept upon yourself not to write further until such a time.' And so he did."
R. Chaim Palagi writes that the reason R. Shimon bar Tzemach Duran (the Tashba"tz) merited to have his teshuvos printed in such a beautiful manner (large size and good binding) more than the other books of his days was because he was always careful to spread an honorable cloth over the open books he was learning from.
קיצור של"ה מסכת שבועות עניני לימוד הנערים
יפה ללב ח"ג (חיו"ד) סי' עז"ר סק"ג
ועי' בספרו רוח חיים ח"א סי' עז"ר
See here, and here

Don't Leave Your Sefer Open

When one learns Torah from a sefer and they wish to get up and take a break, they should not leave the sefer open. In fact, the Sha"ch writes that "It's known to the scholars of truth that there is a certain angel named ש"ד which stands for שומר דפים - Guardian of the Pages. [This angel] ensures that he who walks away from an open sefer will forget his studies."
R. Moshe Chagiz, author of Mishnas Chachamim (brother-in-law of the "Pri Chadash") writes that he heard that the "true scholar" R. Chaim Benveniste (author of the "Kneses Hagedolah") had a silk cloth that he would use to cover the seforim he was learning from when he would walk away from them. Because he was so busy, he did not have time to close them and find his place again, so he used this method.
ש"ך יו"ד סי' רע"ז סק"א
משנת חכמים סי' ר"י
ועי' ספר חסידים סי' תתקי"ח
See here

Brich Shmeih in Middle of Davening

Someone once told the Rebbe in 1949 that he heard in the name of the Rebbe Rashab that one should interrupt in the middle of Pesukei Dezimrah and recite בריך שמיה. The Rebbe asked the Frierdiker Rebbe, and he said that one should not do so. The Rebbe writes "...being that Alter Rebbe does not bring this in any place, us Chassidei Chabad should not do so."
[Interesting to note that the Alter Rebbe does not bring the concept of reciting בריך שמיה at all!]
Not only that, some rule that even if one is holding in the middle of והוא רחום, i.e. tachnun, they shouldn't interrupt for בריך שמיה either!
אגרות קודש כ"ק אדמו"ר ח"ג ע' קמט, עי' בהנסמן שם
שו"ת שבט הלוי ח"ז סי' יב
See here, and here

Vayehi Binsoi'a & Brich Shmei

As the Aron Kodesh is opened, the congregation recites the pessukim of "ויהי בנסוע" and the Aramaic paragraph of "בריך שמיה." When exactly is one supposed to say them, and what if one didn't get a chance to do so when the Aron was opened?
R. Efraim Zalman Margolis, author of "Sha'arei Efraim," a major work on the halachos of krias haTorah, writes: "When they open the ark to take out the Torah, the congregation recites ויהי בנסוע. When they begin to remove the Torah from the Aron, the congregation recites בריך שמיה." Apparently, בריך שמיה is only recited after the Torah has begun its way out of its holy home.
If one didn't recite בריך שמיה then, he should recite it when the Torah is lifted - during hagbah. At that time, the congregation bows to the Torah, befitting the words (of the בריך שמיה liturgy) "...that we bow before Him and before the glory of His Torah..."
שערי אפרים שער י' ס"א עם פתחי שערים שם
ועי' אליה רבה סי' קל"ד סק"ד בשם סדר היום
ועי' שו"ת אגרות משה או"ח ח"ד סי' ע שכתב דמכיון שדין זה אינו מוזכר בראשונים, אין שייך למחות בדבר, ואין מדקדקין, ע"ש
ועי' בשו"ת אז נדברו ח"ח סי' מ"ח (ובספרו בית ברוך על החיי אדם כלל לא ס"ק ר"ז) בענין זה
ועי' בס' דרכי חיים ושלום אות קצ"ו שבעל המנחת אלעזר הי' אומרו כשהי' מונח בארון
See here

Sit When You Bentch

After one has finished their meal, the Torah tells us to thank Hashem for the food by reciting birkas hamazon. The recital should be said sitting, as this helps increase concentration and focus.
Tosfos brings in the name of R. Moshe Albert (see reference) a hint from the Torah itself for the sitting requirement: The passuk says "ואכלת ושבעת וברכת - and you shall eat and be satisfied, and you shall say grace." The latter two words can be split up to read "שב עת ברכת - sit at the time you say grace."
Interesting to note, R. Yosef Chaim of Baghdad, the Ben Ish Chai, would say that this teaches us to sit when we eat as well, as we can understand the hint of "שב עת - sit at the time" as a reference to the word preceding it "ואכלת - when you eat."
תוספות ברכות נא, ב ד"ה והלכתא
אמרי בינה (להבן איש חי) חלק "עושה פלא" פרק ב אות טו
ועי' ספר "תוספות איוורא" למס' סוטה שדן בארוכה בהמובא ששם "אלברט" היא טעות וצ"ל משה מ"איוורא", מגדולי התוספות, רבו של ר' יונה מגרוגדי - בעל עליות דרבינו יונה
See here

Status Switch

The kohen enjoys an elite status even today. He is called up to the Torah first, he gives the special brachah of birchas kohanim, and enjoys other privileges as well. In the times of the Beis Hamikdash, the kohen was most certainly special as he was privileged with the holy task of the daily service.
The levi'im too were special, as they were charged with the job of singing in the Beis Hamidash, but they don't compare to their elite brethren.
Kayin was the first born son; after him came Hevel. Kaballah explains that Kayin was conceived in sin, and as such, the privilege of kehunah was taken away from the first-born and given to the kohen. It is explained further that the levi shares the same spiritual components as the first-born.
Thus, when Moshiach comes, things will change. At that time, the sin of Kayin will be purged, and so, the kohanim will be downgraded to the status of levi'im and the levi'im (representative of the first-born) will be upgraded to their rightful status of kohanim.
לקוטי תורה מהאריז"ל יחזקאל
See here

Say it With Song

It is an age-old custom for the kohanim to recite the brachah of birchas kohanim with a melody. There are various melodies in different communities, each according to their tradition.
Accompanying the brachah with song is no small matter. In fact, when the Torah records the commandment of Hashem to Moshe to bless the Jews, He tells him "...speak to children of Aharon... אמור להם - say to them." The word "אמור" is written out in full - with the ו. As such, the gematriah of the word is 247, the same gematriah as the word "זמר - song."
פענח רזא פ' נשא עה"פ דבר אל אהרן... אמור להם
ועי' בטור סי' קכ"ח בשם הירושלמי ובב"ח שם
לבוש סי' קכ"ח סכ"ב
ערוך השולחן סי' קכ"ח סל"ה
See here