I have heard about building a team using this concept and I have an idea as to what it is, but can someone please clarify it for me and explain how to calculate it?

I do pretty well with the teams I make and I do not make my teams with this concept, I just try to make teams with figures I like to use and that I think work well together.

For me when I build a 300pt team I tend to think that I'll pick a character no more than 150 then a character close to generally 100pt I throw in a UB and a support piece and I have a team however I usually end up using a 130ish point piece and a 80ish point piece allowing for more support or Zuvembies. I hope this helped but I'm not sure what the concept is anyways bu it sounded like it was similar to that.

It's the philosophy of creating your team using only the most powerful, efficient characters and items to make the most winningest possible combination, with absolutely ZERO concern for theme, fun, or comic book sense. Only winning matters. Use any rule loophole and exploit any weakness in the game to win. In the past, min/maxers used the Structural Integrity Field, or L.A.M.P. teams, or Big Barda or the Bug. Nowadays I guess they'll go straight for the Justice League Team Base.

The term comes from (I think) the game Dungeons and Dragons, where a min/max player would create a character who was nothing more than a collection of statistics designed solely to win in combat using skills or gear from a vast collection of resource books that would all combine to be unstoppable. Such a player wasn't there to take part in the story, develop a memorable role or enjoy themselves, but strictly to show off their rules tweaking and mastery.

It's kind of a disparaging term, to describe an over-competitive person or playing style that REALLY doesn't understand the true purpose of social games, doesn't grasp how they are different from sports, gambling or video games.

At the risk of riling the hornet's nest, I will say this about the "break the game at the expense of fun" logic:

Some people really like to do in-depth research about game mechanics and how pieces interact; their fun comes from finding those loopholes or combinations and making use of them, not maliciously, but as a show of creativity or an expression of their own intelligence. To use a Magic: the Gathering psychological "player profile" that Mark Rosewater came up with, these guys are the "Johnny" types.

Others find those guys' findings and decide to run with it because they really do want to win at all costs - whether because they only find things fun when they win, they have a fragile ego that requires occasional validation, or because the prize on the line is really freakin' sweet (or worth a ton on the secondary market) and they want the best odds at being the one to walk away with it. These guys are, to again use a Magic player profile, the "Spike" types.

Anyway, back to the subject of what min/maxing is and less why it's done.

In DnD, which Bill suggested as the term's origin (also referred to there as "being a munchkin," hence the Steve Jackson Games' card game of the same name), it can sometimes involve taking innumerable, practically-inapplicable flaws for your character in order to increase the number of feats they have access to ("Sure, my Wizard gets a -2 to melee attack rolls; in exchange, I'll use my new feat to make it so that my spells are practically impossible to resist, especially the Save-or-Lose ones that wouldn't require a roll regardless - oh, there's a Flaw that gives me a -2 on my Ranged attacks, too? Let's add that and grab another Feat to make my spells even more impossible to resist").

Done well, it can actually help to accentuate a character's unique strengths and their unique weaknesses and improve the "fluff" of the character. Done poorly, or abusively as in my parenthetical hypothetical above about the Wizard, it can lead to, as Bill also suggested, the implication that your mentality is "win at all costs" to the detriment of the fun all around (Does the DM balance his encounters against the party, but have them trivialized by the Munchkin? Or balance around the Munchkin and make everybody else even more useless? A rough decision, to be sure; the correct answer is "ask the munchkin to rein it in; if that fails, remove the munchkin from the table in some way").

In HeroClix? It's theoretically easy to inadvertently Min/Max by way of simply trying to build a powerful team - if your knowledge of comics is less than perfect, for example, you might build a team of "Avengers" that utilizes characters who were never on the same instance of the team together, but are nevertheless among the absolute best pieces for what they do on the table, and all have the Avengers keyword making it a legitimate theme team. This would provide you, in addition to a slew of exceedingly effective pieces, all the bonuses that come along with building to theme. However, somebody who didn't know better might well accuse you of being a munchkin, or of being a fun-hating min/maxer, or what have you.

To make that lengthy explanation short:
Minimizing your team's (or character's, or deck's, or whatever else have you) weaknesses, Maximizing their strengths. The use of the term is generally negative and it implies that you do so at any cost - including at the cost of fun.

Okay thanks guys. Yea I do try to make good teams (but who doesn't) but I never think about it in a min/max way like you guys just stated. It sounds like someone who would just be totally pissed if they los