I know I've seen mentions of this...and achievements can be gotten but how do I do it?

When you dance there is a link to go to the ballroom. When you go there, there is a chance that you will get a popup that will allow you to duel with him. And then it brings up a little paper rock scissors type game. There is an achievement for losing and one for winning.

When I dance where? I've not seen a link to do so.

You need to go to the dance floor. When someone accepts a dance from you, in the event you can click a link that will take you to the dance floor. When you Accept an invite, you also get a link that will take you to the dance floor. You generally have to go to the dance floor often to trigger the event, but eventually you will do so. Then you just click the button (I think there is only 1 now - but its the red one), and you will get a rock paper scissors type of game with weapons, just pick your weapon until the game ends and you win or lose.

EDIT too slow!

You ask people for dances or vice versa. If you go on the Masq forums they have boards where you can find people to dance with.

I've been on the forums and I don't see a "go to dance floor" option or link...

You get it when you dance. I just offered you a dance. Accept it. Then you will get an image of me, some text and below that a link that says something like "Go to dance floor"

When someone accepts your dance offer, you will get an event on your dashboard, and the link is in that event.

Ok, so I'm on the "dance floor" part, now what?

Do I need to keep an open tab of me on that page now?

No, you'll just get a pop-up as soon as the page loads if Boudewijn challenges you to a duel. You need to check every dance link for a challenge until you get the achievements (you might be able to refresh and get a challenge but I don't know, I've never gotten one that way)

Ok so every dance I'm asked to I need to click "go to ballroom?"

Unfortunately, yeah

Yes. Its a huge pain. You'll have to go lots and lots of times to trigger the event.

You can also go when people accept your dance requests, click on "Your proposal to dance has accepted" in the event.

Blah ok got it. Thanks all. We'll see what happens