Shrove Tuesday.
Shrove derives from "shrive", which means to give absolution. So, while I don't know how many parishes offer confession the day prior to Ash Wednesday, that's what it refers to.
It's also called Shrovetide, the evening before the Shrove, which makes more sense, really, reflecting the penitential nature of Lent.
Pancake Day.
It's also Pancake Day in England and strongly English countries, for the custom of eating pancakes on this day. Pancakes use a fair amount of fat in them and this was part of the Lenten practice of abstaining from fat during Lent. It's also therefore one of the odd little ways where England's history as a once deeply Catholic nation is retained.
In Ireland the day is known as Máirt Inide, from the Latin initium (Jejūniī), "beginning of Lent". It's still associated heavily with pancakes. That's sort of indicative of Ireland's history of being heavily impacted by the English.
Of some interest here, potentially, the Anglican Church retains confession, but not the requirement that its members annual confess, like Catholics have. Catholicism is now outstripping Anglicanism in actual practice in the UK. It's often noted that Catholicism has declined in Ireland, a prediction that the Church made at the time of the Anglo Irish War when it did not want to become involved in the Irish government and was forced to against its will, but the Irish remain very heavily Catholic.
Mardi Gras.
Of course, it's also Mardi Gras, or "Fat Tuesday", from the custom at one time of trying to use up all the fats in the house on this day, in French speaking countries. Contrary to American belief, Mardi Gras is in fact not unique to New Orleans but occurs everywhere that French speaking people are located.
American Mardi Gras, or rather American New Orleans Mardi Gras, has become heavily Americanized which means, like all American holidays, it's associated with booze. It is always a big party wherever it occurs, but the weird boozy topless event is an American thing, not a real French thing or culturally French.
Carnival and Fastnachtsdienstag
Carnival, from the Medieval Latin carne vale, "farewell meat", is the same holiday in other Romance Language speaking countries. The same sort of linguistic intent is found in the German name for the day, Fastnachtsdienstag. The latter reflects the fact that European Lutherans observe Lent, but in the same fashion as the Anglicans. It's not associated with the same Canon Law that it is with Catholics, but the observance remains.
We've actually touched on all of this, fwiw, before.
All of these days reflected a period when the Lenten fast was much more severe than it currently is. People were using up fats as they wouldn't keep for the forty days of Lent. Now, in the Latin Rite, there's no restriction on using fats at all, the obligation to fast is just on Ash Wednesday and Good Friday, when the obligation to abstain from meat also exist, during Lent. All the Friday's of Lent are meatless for Catholics.
In the Eastern Rite of the Catholic Church the fasting rules are much more strict. Starting on Pure Monday, yesterday, As Catholic News Service explains it:
VATICAN CITY (CNS) — In the eyes of Latin-rite Catholics, the extent of Eastern Catholics’ Lenten fasting and abstinence is perceived as particularly strict.
The traditional Byzantine fast for Great Lent includes one meal a day from Monday to Friday, and abstinence from all animal products, including meat, fish with backbones, dairy products and eggs, as well as oil and wine for the entire period of Lent. Shellfish are permitted.
Fasting and abstinence are maintained on Saturdays, Sundays and on the eve of special feast days, although loosened to permit the use of oil and wine. On important feast days, such as the Annunciation and Palm Sunday, fish may be eaten.
“Oil and wine were restricted because, in the past, they were stored in animal skin,” explained Mother Theodora, the “hegumena” or abbess of the Byzantine Catholic Christ the Bridegroom Monastery in Burton, Ohio. “Though this is no longer the case, the tradition continues.”
There are varying degrees of fasting, from stricter to more lenient, depending on one’s work and state of health. Monks and nuns will often submit to the most strict fasting.
Holy Week is not considered part of Great Lent but “an additional, more intense time of fasting and prayer,” said Mother Theodora.
However, Eastern Catholics don’t plunge into fasting and abstinence cold turkey. “Meatfare” and “Cheesefare” weeks help them enter into the Great Fast gradually. By Meatfare Sunday, one week before the start of Lent, Eastern Catholics will have emptied their refrigerators and pantries of meat products. By Cheesefare Sunday, they will have cleared out all of their egg and dairy products, ready to enter into the Great Fast that evening, after Forgiveness Vespers.
In an effort to keep Eastern Christians faithful, yet creative, in the kitchen, cookbooks with fast-friendly recipes have been published.
By Laura Ieraci, Catholic News Service. The rules for the Eastern Orthodox are similar, although I'm never certain of the degree to which the Orthodox are required to observe them. Orthodox churches using the "Old Calendar" start Lent this year on February 23.
With all this, Catholics in the US enter Annual Question Time and the time of slightly difficult observances, the latter taking note of the fact that unlike some past times in the country, we're not likely to get killed or anything, so its nothing like it used to be. Rather, as the US is not only heavily Protestant, but Puritan, Lenten practices baffle non Catholics.
Puritans disapproved of pretty much everything, including observing Christmas as a special day, so Lent was way beyond the Pale for them. English culture, on the other hand, loved sports, so when the English dumped the Calvinist, which they did as soon as they could, their love of sports came roaring back. American culture has been impacted by English culture in every way, so Americans love sports but don't understand the Apostolic Faiths very well, in many instances, and in fact sometimes fail to realize that their own branches of Christianity are fairly recent innovations not reflecting the original Apostolic faith.
So for Lent, including its beginning, and its end in Holy Week, Americans just don't really have any observations, other than using Mardi Gras, like St. Patrick's Day, as an excuse to drink. They way it shows up for Catholics, however, is that things that are fairly easy to observe in Catholic countries, like Holy Week or Ash Wednesday, are a lot tougher to do in the US, and of course, you'll be getting a lot of questions if you are Catholic about "why do you do that" and "why can't you . . .".