I've done a few things myself for the wedding, and my current DIY project is these tissue paper pom-poms from Martha Stewart.
The idea is to bring some color into the space and bring the eye upwards. I think they're turning out really cute! The only thing I'm worried about is bringing 30 of these guys up into the ballroom and not being able to hang them. Haha, oh well. I'm going to ask about that when we go to make our final payment.
Here's a picture of the ones I've done so far:
They're a pretty fun and inexpensive way to make cute decorations.