I came across a few sites that could be used for word fun and learning tonight on a blog I read regularly. 
Does anyone have anything else "wordy" online that we and our kids might like? 
the blog post- 
http://missrumphiuseffect.blogspot.com/2011/08/blooms-digital-taxonomy-pyramid.html.  The post has a link to another resource that folks here might find useful for online activities (many interesting links here, I'm still clicking around)
http://www.usi.edu/distance/bdt.htmSome sites from these resources I thought were particularly cool-
http://visuwords.com/     visual dictionary
http://www.wordnik.com/  they call it a "dictionary on steroids"
http://www.periodicvideos.com/videos/008.htm   not words, videos on the elements
another site I was reminded of - 
http://www.wordle.net/  word cloud generator