One of the best ways to go green is to encourage recycling, or to produce very little need to recycle. Encouraging electronic files and slideshows versus weighty and paper-heavy handouts is one way to get off to a green start. If paper is a necessity for the event, however, providing easy access and good signage for recycling bins or shredders will cut down on the trash, while lightening up the load for your guests on the way out.
Having staff or hired caterers clear tables also makes sorting and recycling a seamless part of the event while making attendees feel well-taken care of and free to circulate without fear of being seen dropping plastic in a paper-only bin -- which can cause anxiety these days!
Sometimes, the most memorable business event is the one that goes the smoothest, causes the least amount of hassle and leaves you free handed, but with a head full of information versus a bunch of paper bricks to file and toss. Going simple and light is good business -- and green business.