A recent ParentingIdeas.org article talks about the benefits of boredom:
Strange as it may sound, bordom [sic] promotes happier, creative kids who are better problem solvers. When children use their own creativity with unstructured play, they find ways to amuse themselves — even if it means simply daydreaming.
This has been our plan for Ruby all along. It’s why she doesn’t watch any TV right now, and why we’ll keep her organized activities to a reasonable level when she’s older. It also makes me feel better about the time she spends exploring the playroom alone while I’m in the next room writing blog entries.