Like mentioned above, fold the paper in half, punch holes along the left hand side (of both sheets), and put in my planner. Not easy to open to see the whole page.
I've also punched holes along the 8½", place in planner and fold the paper in half to meet at the rings. Don't like the paper overlapping the rings.
The third way is by not using the whole sheet at all - I've often retyped what I've been given on to a half sheet of paper or shrunk it to fit a half-size sheet. Not very convenient.
After reading Giftie's post on Temporary Planner Pages I started playing around with my paper and figured out how to store them and make them easily accessible
I take my sheet of paper (below I'm using my Sunday School notes), fold it in half and hole punch it through both layers. Open the sheet up horizontally and place the left side in the rings and close it up. Take your scissors and cut through the holes on the right hand side. Now you will be able to completely fold over your paper and fit them into the rings. I rounded the corner of the paper to make it easier to grab a hold of and lift the page up to read the entire page