Ideas for simpler, greener birthday parties

Kids' birthday parties have gotten a little out of hand. Though my kids have never attended an over-the-top party, I've read and heard stories about them and how the bar keeps getting raised higher and higher. Julie emailed us looking for ideas for eco-friendly birthday parties. She writes:

This topic is covered in one chapter of the "Healthy Children, Healthy Planet" course, but I am always looking for other ideas on what families do to encourage "sustainable" birthday parties.

My mom recently sent me a link to a site called Birthdays Without Pressure, created by a group of Minneapolis parents who want a return to wholesome, simple parties without the excess. And there are a lot of ways to reduce waste, such as using Evite for invitations, encouraging attendees to bring gifts in reusable bags or wrapped in newspaper and foregoing the goody bag filled with cheap trinkets. I was so impressed by Renee's post on ReadySetMom about a friend's party for her daughter, and love the idea of asking guests to bring a donation of toys, food, clothing, whatever for a worthy organization. I think you really have to talk about it to your kids and make them understand they will receive gifts from family members, but that we need to think beyond our own wants. The GreenGuide, TreehouseTV and this site also offer ideas for green parties. 

What ideas can you offer to simplify and green-up birthday parties?