Knee Exercises
Hold you leg ALL the way up,
with the knee straight.
Bend your knee only slightly, as shown.
Repeat this exercise 10 reptitions, and perform at least three sets a day. 

Add a one pound ankle weight, or use an empty purse with a can of soup or tuna fish on the end of your ankle to add resistance.
Quad Sets: The first exercise is to simply sit in a chair, and tighen your thigh muscles.  Hold the contraction for at least six seconds.  Repeat this six times and do at least three sets a day.
Short Arc Quads are the second set of exercises:
Links:

Piedmont Physical Medicine and Rehabilitation

We Help What Hurts

Exercise Pictures Home

Gluteal Sets for Low Back Pain

Abdominal/Back Exercise

Sacroiliac Exercise

Back/Legs Exercise 1

Back/Legs Exercise 2

Hip and Knee Exercise

Neck Exercise

Shoulders Exercise

OA Exercise

Scapulo-Thoracic