-Sit
-Rest (right or left) foot on opposite knee
-Gently lean forward with strong, straight back (engage abdominal and low back muscles)
-Feel a stretch, possibly some discomfort.  No pain.
-Switch sides

-Side of (left or right) foot touching edge doorframe (Standing somewhat behind the doorframe, as seen in photo)
-Feet hip width apart
-Whole body faces forward
-Bring arm (closest to doorframe) up and back, touching the shoulder blade
-Elbow of raised arm rests lightly on doorframe
-Turn head and neck only, toward the opposite foot's small toe

-Stand in middle of doorway
-Feet hip width apart
-Raise shoulder 90*, bend elbow 90*
-Rest forearm on doorframe
-Lift instep of OPPOSITE foot
-Twist whole body (pelvis, torso, chest, head) away from raised arm
*Play with heights of the raised arm to effect different muscle fibre angles

-Place ball of foot against wall, heel touching ground
-Knee straight (gastrocnemius stretch) or knee bent (soleus stretch)
-Lean whole body toward wall

*Stretches side benders of the low back, along the rib cage and parts of the armpit
-Sit on feet (place pillow between heels and buttocks if this is too hard on your knees)
-Curl forward, reaching with hands
-Slowly walk hands over to one side of the mat
-Return to neutral, and go to the other side

-This is a great stretch if you're body is capable.  There's no need to go right to the more advanced position.  If needed, allow your body to remain propped up by the hands in front (like in the second picture) until you can straighten the back leg further.
-This position may be hard on the back depending on your history so if this is at all painful, come out of it slowly.  
*This stretch may not be appropriate for those with problems extending the low back, or problems involving the knee.

-The muscles this pose will be stretching are the HIP FLEXORS, the ABDOMINALS, the deep muscles in the GLUTES that rotate your leg out and the QUADS on the front of the thigh if you can bend your knee.  It is also an excellent way to work on SI JOINT FLEXIBILITY (triangular bone at the bottom of the spine).

-Start on hands and knees
-Bend (right or left) knee and bring leg forward
-Front leg/foot crosses in front of body
-Slowly straighten back leg (still supporting weight on hands)
-Gradually raise torso up (it's ok to remain bent forward)
-Bend back knee to stretch quads (advanced)

These are fairly straight forward stretches that most everyone has seen before.
-Keep knees close together in standing quad stretch
-Keep hips straight (Don't let the knee point forward or back as you hold the foot)

*Cat not required, hehe

-Sit with knees bent
-Cross (left) leg under so the knee points forward
-Bring (right) ankle to other side of the bent (left) knee
*Goal: To have both cheeks seated on floor as demonstrated in last photo
-Reach (left) arm upward, lifting torso, straight back
-Twist
-Rest (left) arm/hand on (right) knee/thigh/hip depending on level of flexibility
-Look back, keeping upper body tall

*Fourth and fifth pictures are just views from different angles; same pose

This stretch is good for opening up the hips and stretching some of the muscles that sit on the inner thigh and in the glutes.
When bending forward keep your back strong and straight.