I wasn’t around for the Cuban Missile Crisis, so can some Baby Boomer SDopers tell me: Did Kennedy give Castro an ultimatum with or without UN approval? (Hello, Mr. Administrator! This is a factual question since it is based on history!) - Jinx
I thought the Cuban Missile Crisis was mainly a standoff between Kennedy and Khrushchev, not so much Castro. That said:
From this page.
Ice Wolf, thanks for the correction. Not having lived through it, I always assumed it was Castro who was the main player…since it was his land, Cuba. (Wouldn’t it have been easier for the USSR to place missiles near Alaska?) Is this all related to the deal with Khrushchev banging his shoe at a UN speech? If not, what was that all about? Sorry, but we never could get this far in History classes! 
Heck, today you’re lucky if US kids can find California on a US map! - Jinx 
Khrushchev apparently did the shoe-banging on a UN conference table in 1960, in high emotion, Jinx. It wasn’t directly part of the missile crisis of '62.
Short version:
There were US missiles in Turkey, able to reach cities in Ukraine and southern Russia in a few minutes, and the Soviets didn’t like it (well, duh). To tip the balance they wanted to place missiles in Cuba. The Soviets told Castro that the Americans were planning to attack Cuba, and offered to place missiles there to make them think twice about it. Cuba accepted in the interest of its own defence and for the common good of socialist, but the Russians built and controlled the missiles, so apart from saying ok, the Cubans had little to do with it.
Cuba is a lot closer (to the major targets), meaning that the US would have very short notice to respond.
Did Johnson appeal to the UN regarding Viet Nam?
It would appear that Johnson corresponded with the then Secretary-General of the UN over “solutions” to the Vietnam conflict in 1965 (cite). The American ambassador made a number speeches to the UN regarding such solutions. Whether you could class that as a “appeal” to the UN is in doubt.
For good background on this, go to your local Blockbuster and rent The Missiles of October. This was made in 1973 and AFAIK gives a pretty accurate portrayal of events from Kennedy’s perspective. There’s also the more recent movie Thirteen Days done by Kevin Costner.
We were a bit short of adequate reason for being there, too, especially as time went on.