In a real tournment can you play 2 queens?

You joking Shadowknight!  

Oh my gosh, I'm laughing my head off here!

That is the one and only reason why I would personally never do anything like that. When the game is won, one tends to lose a bit of concentration.  It's only human I guess.

Not so long ago I was playing a lower rated opponent in an online tournament match.  21 moves into the game I was three pawns up and instead of just playing normal, my head blew up to three times it's size with overconfidence and I took the fourth pawn, leaving myself wide open for attack.

We drew the game in the end, and it was only because I offered the draw and my opponent didn't see the win.

Depends which rules are in effect.  From the USCF rulebook:  "It is a common practice, however, to play using an upside-down rook for a second queen.  In the absence of the player's announcement to the contrary, an upside-down rook shall be considered a queen."

Its easy enough just to reach over and borrow an extra queen from the board next to yours. 

Try interrupting the game next to yours to do that lol. Would probably work if the queen you needed was of the same color as the neighboring player who has an easy win and a lot of time on the clock. But then his opponent would get all upset for being distracted. The tourney players can get upset pretty easily lol

Exactly. That's why the player who dragged out the game to humiliate his opponent deserved what he got.

here is a game between IM's or GM's where there were five queens ion the board at one time:

http://www.chessgames.com/perl/chessgame?gid=1316515

There was a famous Alekhine game that involved five queens (though this may have been a doctored score by Alekhine, who wasn't above presenting a possible sideline as the actual route the game took if it made him look better). Also on http://timkr.home.xs4all.nl/chess2/diary_15.htm there is the score of another game I heard of (Tresling vs Benima, 1896) and one or two more.

Yes you can. Mostly, a pawn promotes to a queen. Multiple Queen is OP

There were a dozen guys who already answered that question in this thread 10 years ago. Your contribution is surely very valuable after all this time has passed.

3.7.5.1
When a player, having the move, plays a pawn to the rank furthest from its starting position, he must exchange that pawn as part of the same move for a new queen, rook, bishop or knight of the same colour on the intended square of arrival. This is called the square of ‘promotion’.
3.7.5.2
The player's choice is not restricted to pieces that have been captured previously.
3.7.5.3
This exchange of a pawn for another piece is called promotion, and the effect of the new piece is immediate.

https://handbook.fide.com/chapter/E012018 

The fact that you can have more than one Queen on the board is in itself peace manipulation and ultimately a form of cheating. Just because it's a rule does not justify the action. The truth is. If you lose one piece and you only have one piece to lose. You should only receive one piece back. A queen for a queen. How bad do you have to be at the game to literally create pieces to win? Lol

It is allowed. Usually, there will be an extra queen. If you already have 2 queens, you can just borrow the queen from the board beside you (ask arbiter first)

most serious tournament games will not have more than 2 queens per player anyway

Yeah, but if the opponent just wanna but brutal, this is likely.