The wedding party is not a party in the sense of an event, but rather a group of friends and/or family members who support the couple before and during the wedding. The wedding party consists of the bridal party, i.e., the maid of honor and the bridesmaids; and of the groom's party, i.e., the best man and the groomsmen. The bride and groom usually select the same number of bridesmaids and groomsmen since they are "paired up" when walking down the aisle. It is entirely up to the couple how many people are in the wedding party, however, it usually consists of 3-6 bridesmaids and groomsmen. On the day of the wedding, the wedding party can be recognized by their attire: The bridesmaids usually wear the same color. (Often, they also wear the exact same dress, although the trend these days is leaning towards individualized outfits.)
Prior to the wedding, the bridesmaids and the maid of honor usually throw the wedding shower (an informal party, most often only for the bride and only with her female friends, with games and presents) and the bachelorette party, while the best man traditionally organizes the groom's bachelor party. The wedding party also supports the couple in the wedding planning and preparations, and shares closely in the excitement of this special phase in the couple's life. Here you can find some interesting information about the wedding party and its members:
After the ceremony, the newlyweds and the wedding party line up, so that all guests can congratulate the couple, say hi, and get introduced to people they don't know.
This tradition came from Holland. When a poor woman's family did not have the money to provide a dowry for her, or when a father refused to give his daughter her dowry because he did not approve of the marriage, the villagers gathered to "shower" her with the dowry she didn't have. The custom remains a primarily US and Canadian practice. Showers are usually coordinated by the bridesmaids, who invite guests to offer gifts for the home of the bride and groom. These days, showers are more and more often co-ed, with friends of both the bride and the groom attending.
The rehearsal is there to rehearse the wedding ceremony. The bride and groom, the wedding party, and the parents of the couple and close relatives meet at the location of the ceremony on the day before the wedding and practice the sequence of events together, so that everyone knows where to be and what to do on the big day. Afterwards, the rehearsal dinner takes place.
In the US, couples don't get married at the Standesamt – there is only a single ceremony. This ceremony can take place wherever the bride and groom want it to be. After the ceremony, the couple signs the marriage certificate, which constitutes the legal marriage.
This is a Polish and American tradition: The bride and groom thank their guests with a small present. This has to be neither expensive nor a present in the traditional sense. It's just a small gesture to remind the guests of the beautiful celebration.
When the guests clink their silverware against their glasses, the newlyweds have to kiss. Most often a few guests start clinking, then others join them, until the entire room resonates with the sound.
The dollar dance originated in Poland in the early 1900s in immigrant neighborhoods. The concept is that the male guests pay a dollar (or more ;)) for the privilege of dancing with the bride, and by extension, female guests pay for the privilege of dancing with the groom. (It's also possible for the female guests to dance with the bride and the male guests to dance with the groom.) The money is collected by the maid of honor and the best man and is to be used for the bride and groom's honeymoon or to give them a little extra cash with which to set up housekeeping. The dollar dance usually lasts 2-3 songs, and each guest may dance with the bride or groom for about half a minute. At the end of the dollar dance, it is customary to tally the money and announce who collected more. The bride usually wins. :)
The bachelors among the guests gather behind the groom. He removes the garter that the bride is wearing above the knee. Then he tosses it blindly into the group of bachelors, just like the bride tosses her bouquet. (German tradition has it that the bride's garter is auctioned off among the bachelors.)