I used to do chemistry shows for outreach, and I have just the reaction for you.
It requires a chemical called Luminol and a few other readily available compounds like sodium bicarbonate and copper sulfate. Overall, pretty environmentally friendly, but you should check the individual chemicals to make sure they don't require any special disposal. I don't think they do, if you're not using huge amounts.
Check out this website with the directions:
http://chemistry.creighton.edu/Outreach/MMM/2001chemistry.htmlBasically, you have two solutions that will mix and produce blue, shimmery light. Pretty cool. You'll need to do it indoors where you can dim the lights, though. There is a video of the chemistry show number that uses this reaction, this reaction in particular is near the end of the video.
Congratulations on the wedding!