Although this is in Sandy, the Living Planet Aquarium is a fun, interactive place for kids to learn about those who live in water.  Currently they are offering $3 off of admission which is a great deal!  It expires 8/31/2011.

725 East 10600 South, Sandy

Admission:

$9 for adults
$8 for seniors, students and military
$7 children (3 to 17)
Ages 2 and under are FREE