I just love this idea and have seen it at wedding receptions, rehearsal dinners and showers. If you aren't shy and have a way with words, more specifically lyrics, then you may want to think about singing a toast to the bride and groom.
Here's the link to the article, To the Happy Couple, and My You Tube Clip with links to some of the clips mentioned in the story.
If you know of or have performed a parody at a wedding or pre/post-wedding event I'd love to see the clip -- and I'm sure other readers would too!