Kids' races
Kids usually don't run in races. However, grade school kids can often be attracted to events if there is a kids-only race.
The CVS/Caremark Downtown 5k, in Providence RI, offers 21 heats for kids from pre-school to 8th grade. Distances vary from 50 meters to 1,500 meters and are tightly scheduled before the running of the main event.
If you offer kids races, treat them as real events, not add-on entertainment. Here are some tips:
1) Be sure the distances are accurate. Kids are entitled to the same quality as adults.
2) Don't offer competitive awards for kids under six years old. Participation, not winning, should be the goal. Give everybody an award.
3) Allow parents to run with small children. Sometimes it's the only way to get the kids to run.
4) Give the kids goody bags with stuff they want. Toys, coloring books, or reasonably healthy candy are good choices. No instructional information about running and nothing that reminds kids of school.