It does not matter whether you are a beginner or a pro at dynamic stretching. Some basics are swinging you arms in a out (giving yourself a hug) and kick your legs back kicking your bottom.
Tubing exercises are great for people with joint pain. The exercises are usually fairly low impact and do not require a lot of awkward bending or stretching of muscles.
http://www.momentumsports.co.uk/TtDynamicStretches.asp has a wonderful site onshowing you the best way to do your streches. They have warm ups and warm downs. This is a great site.
There are a variety of exercises someone could do to help strengthen their calf muscle. Single-leg and double-leg calf raises are a great exercise for your calves as well as stretching and running.
Try a library or a book store for books on exercises. Pushups are excellent exercises and free. Sit ups are great and free. First you should start with stretching exercises, which are also free.
A bowflex is a great fitness machine and set for beginners who are just starting to work out. It is a great product and I seriously recommend it to any beginners.
They should do whatever they are capable of. Gentle stretching exercises and slow control exercises help a great deal. Loss of muscle mass is a big deal as people age so anything to promote and maintain core stability is a good thing.
Avoid doing exercises that impel high pressure on your knees. Going for a 30 minutes walk five days a week would be of great help. Jogging is a good one, too. After warming up try to do some stretching moves.
Yoga is a great way to exercise and strengthen the spine. Even something as simple as stretching can be used as a perfect spinal exercise as it allows you to relax the joints.
Betta's or Goldfish.
I would rather suggest stretching than traditional exercises! A carefully create stretching routine can help you alleviate pain/muscle stiffness while mobilizing the sciatic nerve! Combine some hamstring/lower abs/torso stretches, be careful when applying them (you need to follow specific guidance in order to make stretching harmless) and i am confident you will soon see some great results!
The following website has many videos on using exercise balls: http://www.fitnessmagazine.com/videos/exercises/exercise-ball.htm These videos are instructional and provide great how-to information for beginners and fitness enthusiasts alike!
one great book for beginners is Haircutting for Dummies by J. Elaine Spear