Spring is here, the wedding season is upon us. If you get invited to a wedding, remember: this is someone's special day. Don't mess it up for them. Never, under any circumstances, ask when the baby is due. If the invitation says RSVP, that means let them know you're coming and do it before the day before. Don't bring extra guests of your own especially if he or she was at one point romantically involved with the bride or groom. When the minister asks if anyone objects, don't say anything, even if you have very strong premonitions. At the reception, don't hand out brochures for your business enterprise even if it is something really good, like homeopathic vitamins, and don't invite people out to the parking lot to look at merchandise.
Circulate at the reception. Don't hunker down in the corner like a trapped rat. It makes people nervous. Keep the conversation light. There's no need to discuss bankruptcy, felony convictions, time spent in treatment programs, or your own marital problems. This is not the time. Let's talk about alcohol. An open bar doesn't mean that it's your last night on earth. Pace yourself. One glass of wine is enough, don't walk around with two. Same with food. Don't load up a plate so that food is falling off it. And one more thing — if you think that weddings are a great place to pick up girls: it isn't true. Back off. She's just not that into you. And that bridesmaids dress is misleading. Normally she wears muscle shirts and ripped cutoffs, and spends her afternoons playing softball with the girls.
[Text source -- http://prairiehome.publicradio.org/programs/2005/04/23/scripts/wedding.shtml]