By "Teachable Dances" we mean dances that can be taught on the fly, right before dancing the dances.
Writeup of Cha Cha Slide on wikihow.
This is a well known dance, if you are under thirty! :-). Many people will already know this, and the dance gives instruction as it goes (like the Timewarp). It can just be played, and encourage people to join in. Play all the audio from the official video, it talks people through the dance.
Sir Roger de Coverley, is a very old (1695) but still popular dance. It's even mentioned in Charles Dickens "A Christmas Carol". This dance is usually taught by the top couple (nearest the DJ). The DJ announces the song, and people will run out to start a set. This is done by placing themselves in the positions of the top couple and raising their right hands.
The DJ usually announces this with "Please take four of five couple sets to learn and dance Sir Roger de Coverley. If you have more than that, the last dancers don't get to participate fully.
One Note: In the video, after "Bow, Right, Left, Both Hands", they do a step in a hammerlock position, where as we just pass around our partner, using no hands.
The Congress of Vienna is a choreographed waltz by John Hertz.
Note that this document is very terse, to make it fit on one page. Please contact Tom Hill for more details, or if you have any questions.
Of course, if you can reach John Hertz, you can get the answer from the source.
The original music can be found here, but you don't want to use that, as is. The original is eight minutes long. Usually we play a version that is about 4:30. Talk to us, if you need a copy.
Salsa Rueda is a group dance where pairs of leaders and followers dance together in a rueda, or wheel. A designated caller (usually in the rueda itself) calls moves that dancers perform simultaneously, producing beautiful, synchronized patterns. But make no mistake--this is still partner dancing, and many of the moves learned in salsa rueda can be transferred to other dances like Swing and Nightclub Two-Step!
Salsa Rueda is based on Cuban-style salsa, where salsa originated! It has since evolved in many other dialects of salsa, like LA style (on 1) or New York style (on 2). Unlike other forms of salsa dance commonly danced in the US, Cuban-style does not focus on a single "slot" and instead uses a "circular" space around the dancers, resulting in patterns that are markedly different from slot-based dances.