Unity 3 added registration by convention to do the mass registration.
Also, Unity has the concept of registering an unnamed mapping and many named mappings. The unnamed mapping will be resolved when calling Resolve() or one of its overloads. All of the named mappings (and not the unnamed mapping) will be resolved when calling ResolveAll() or one of its overloads.
// There's other options for each parameter to RegisterTypes()
// (and you can supply your own custom options)
container.RegisterTypes(
AllClasses.FromLoadedAssemblies().
Where(type => typeof(IRunOnEachRequest).IsAssignableFrom(type)),
WithMappings.FromAllInterfaces,
WithName.TypeName,
WithLifetime.Transient);
foreach (var task in container.ResolveAll<IRunOnEachRequest>())
task.Execute();