Since I took the time to write this up, I figured I would post it. It's behind a cut, so feel free to ignore it :)

This is information about how things work in the Irish Dance organization I belong to (An Coimisiun le Rinci Gaelacha). There also might be some things that are specific to my region (U.S. Western Region).

The Shoes:

Softshoes (or ghillies or pomps) are the ballet-like shoes that lace up. They are similar to Highland ghillies, but they have loops instead of eyelets.

Hardshoes (or heavies) are the noisy ones. They have leather uppers with fiberglass tips and heels that make the noise.

The Dances:

Reel - Softshoe dance done in 4/4 time. Powerful and quick.
Light Jig - Softshoe dance done in 6/8 time. Emphasis is on proper technique (turnout and crossover)
Single Jig - Softshoe dance also done in 6/8 time, but is more 'hoppy' which is why it is also called a hop jig. Think 'Pop Goes the Weasel'
Slip Jig - Softshoe dance done in 9/8 time. Traditionally a female dance since it is supposed to be graceful and flowy.

Treble Jig - Hardshoe dance done in 6/8 time. The same music as the light jig, but slower.
Hornpipe - Hardshoe dance done in 4/4 time(though the rhythm is different from a reel). Think Sailors :) and apparently 'If I Only Had a Brain' is a hornpipe.
Traditional Set - Hardshoe dance done to a traditional piece of music. There are (I believe) 9 traditional set dances. These are dances that are handed down and everyone learns the same choreography (with slight variations depending on your region). The first one you learn is St. Patrick's Day which is in treble jig timing. Others are hornpipes (Black Bird, Garden of Daisies and Job of Journeywork).

Treble Reel - Hardshoe dance done in 4/4 time.

The Competitions:

And Irish dance competition is called a feis (singular - pronounces fesh) or feisanna (plural - prnounced fesh-ahna). The competitions are based on age as well as level. Your 'Feis Age' is how old you are as of January 1st. (i.e. if you were 11 on Jan 1st, you would dance in Under 12 (or U12)).

There are 4 'grade' or lower levels: Beginner I, Beginner II, Novice and Prizewinner (sometimes called Open, depending on the region).

In the lower levels, you compete with the first 7 dances listed above (reel, light jig, single jig, slip jig, treble jig, hornpipe and traditional set). Each dance is a separate competition (so you have 7 chances to get a medal!).

In order to advance out of Beginner I you need to have placed either 1st, 2nd or 3rd. To move from Beginner II to Novice, you need to place 1st or 2nd. And to advance to Prizewinner you have to place 1st in Novice. This is the tough one. There also needs to be at least 5 competitors for your placing to 'count' for moving up.

All grade competitions are judged by a single certified judge. You dance 2 steps (a step is 8 measures done on the right foot and then repeated on the left foot) and generally danced 2 at a time (sometimes 3 at a time in the younger groups). The stage is small and there are tons of collisions. Good times! Dancers are judged on their technique (feet turned out and crossed over, dancing high up on their toes with their shoulders back and their arms straight at their sides), timing, rhythm and overall presentation.

Here is a good example of a Feis. The girls dancing are in Prizewinner. You can see the multiple stages goingo n at once with two dancers on each stage. They are dancing a reel.

As you move up the levels, the dances get more intricate, so to compensate, the music gets slower. This is especially true with hardshoe dances (not including traditional sets). The lower levels (Beg and Beg II) will do their hornpipes and treble jigs at 'traditional speed'. Some dancers new to the novice level will still do their traditional speed steps until they have learned their 'slow hornpipe' or 'slow treble jig'. It is rare to see a traditional speed dancer in Prizewinner level.

Once all your dances have made it up to prizewinner (and you have also placed well enough in that highest level - this is determined by your teacher) you will move up to Preliminary Championships. This is a whole new ball game.

Preliminary championship competitions consist of 3 rounds and are judged by 3 judges. You have one softshoe round (either a reel or a slip jig), one hardshoe round (treble jig or hornpipe) and then a set dance (more on those later). The rankings for each round are combined to get your overall placing. There are usually 'solo' medals awarded for each round - the rankings from one judge are chosen at random to represent the solo awards.

The softshoe and hardshoe rounds are danced 2 at a time (or three at at time if you are Under 12). The set dance is done one dancer at a time.

Championship reels and treble jigs are 3 steps long (right and left foot) while championship slip jigs and hornpipes are 2 1/2 steps long (the last step is only done on the right foot). This is why the usual combinations are reel/hornpipe and slipjig/jig, so you'll do one dance that is 3 steps and one that is 2 1/2 steps.

Which softshoe and hardshoe dances you do are generally dictated by what dances are assigned to your age group for the regional competitions (though you can technically choose whichever ones you want). You are either a reel/hornpipe or a slipjig/jig (unless you are a gent, then you will always do a reel, only your hardshoe changes).

Set dances (like traditional set dances) are hardshoe dances done to traditional pieces of music, but there is no universal steps, they are choreographed by the teacher. They consist of a step (any where from 8 to 15 bars in length) that is done on the right and left foot, and a set (12 to 24 bars) that is only done once. Here is a list of the set dances. In certain regions in the US, the set dance is offered as a separate trophy special for Preliminary competitions and so their results are based on only 2 rounds.

Once you have won 2 Preliminary championships (with 5 or more competitors), then you will move into Open Championships. These are run the same as Prelims (3 rounds, 3 judges), just waaaaaay more intimidating.

Apart from the regular solo competitions there are 'Trophy Specials'. Most feisanna will offer at least one trophy special for each level. Common specials are the slip jig special, the treble reel special and the boy's special (softshoe reel). Specials are done in a 'step about' style - one step each down the line, one dancer at a time. Treble reel specials are always great fun. When the last dancers is done, the whole line will do a simple step together. It can get pretty loud if it's a big competition.

And I found the end of a treble reel special on youtube!

Besides the local Fiesanna there is the regional competitions (called Oireachtas) that feed into the World Championships. There is also the North American Nationals, the All irelands and the British Nationals (which also send qualifiers to the Worlds competition). The bigger competitions are all referred to a 'Majors'.

As for me, I am in Preliminary Championships and a 'Senior Lady' (in the &Over age group - i.e. 21&Over at Majors and 17&Over or 19&Over at local competitions) and I dance slip jig/jig and I am learning 'Drunken Gauger' for my set. It's sad that in Irish dance you are considered a 'Senior' at age 21.

Don't even get me started on what we wear! or ceili dancing!