As far as small pets go, guinea pigs are among the easiest to
     care for, and also rate high on the cuddliness scale.  You will
     need to feed them and check their water daily, and change their
     bedding about once or twice a week -- somewhat less when they are
     small.  Also, if they are confined to a cage, they need to be
     allowed to run around a larger area for exercise daily.

     Guinea pigs are ideal for (responsible, gentle) children because
     they tend to be sweet-tempered, pettable, and relatively easy to
     catch if they escape from your child's hands -- mice, hamsters,
     and gerbils, by contrast, are able to hide for weeks or more if
     they escape.  They are larger than most rodents (about the size
     and shape of a large tennis shoe when grown), which makes them
     easy to find and to handle.  If you are looking for a highly
     intelligent and sociable pet, you may be looking for a rat
     (seriously).  If, however, you want a sweet, lovable furball who
     will sit on your lap to be petted for hours (well, minutes,
     anyway), a guinea pig may be the pet for you.